JPH08321640A - Ferroelectric element and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a highly sensitive and low cost ferroelectric element. [Structure] (100) on the surface of stainless metal substrate 101
M consisting of NaCl type crystal structure in which crystals are preferentially oriented on the plane
The gO thin film 102 is arranged, and P is formed on the surface of the MgO thin film 102.
The lower electrode 103 composed of a t-thin film is arranged, and the lower electrode 1
A specific portion of 03 is covered with a ferroelectric film 104 made of Pb _0.9 La _0.1 Ti _0.975 O _3, and an upper electrode 108 made of a Ni—Cr thin film is arranged on the surface of the ferroelectric film 104. The etching hole 105 is formed so as to penetrate the MgO thin film 102, the lower electrode 103, the ferroelectric film 104, and the upper electrode 108 to reach the surface of the substrate 101.
01 through the etching hole 105 in the upper layer
A void layer 110 formed by etching away a part of 01 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a pyroelectric infrared detector,
The present invention relates to a ferroelectric element using a ferroelectric film used for a piezoelectric mechanical quantity sensor, a piezoelectric actuator, and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 9 shows JOUNAL of APPLIED PHYSICS 63
(12), 1988 p5868-5872 R.TAKAYAMA et.al is a perspective cross-sectional view showing the structure of a conventional ferroelectric element proposed in
In the figure, 10 is a MgO single crystal substrate, and 11 is P
lower electrode consisting of t, 12 added lanthanum, c
A lead titanate-based ferroelectric thin film having an axially oriented perovskite structure, and 13 is an upper electrode made of Ni—Cr. In other words, this ferroelectric element is composed of the MgO single crystal substrate 1
A lead titanate-based ferroelectric thin film 12 having a c-axis-oriented perovskite structure to which lanthanum is added is formed on 0, and a pyroelectric infrared sensor is formed into a device by using the thin film. In this ferroelectric element, that is, in the pyroelectric infrared sensor, the pyroelectric material (lead titanate-based ferroelectric thin film 12), which is a ferroelectric material, has a polarization direction in one direction without polarization processing. They are aligned, which allows the pyroelectric current to be detected. Moreover, it is possible to obtain pyroelectric characteristics about three times as high as that of the one using the bulk sintered body subjected to the polarization treatment. Further, since the MgO single crystal substrate 10 has a high thermal conductivity, the MgO single crystal substrate 10 located under the pyroelectric material (lead titanate-based ferroelectric thin film 12) is usually etched by etching as shown in the figure. The through hole 10a is formed to prevent heat conduction from the pyroelectric body (lead titanate-based ferroelectric thin film 12) to the substrate 10, thereby increasing the sensitivity of the sensor.

On the other hand, FIG. 10 shows Sensors and Actuators A.
35 (1992) 77-83, C. Ye, et. Al. Is a cross-sectional view showing the configuration of a conventional infrared detector. In the figure, 2
0 is a Si substrate, 21 is a SiO ₂ film, 22 is a Si ₃ N ₄ film,
Reference numeral 23 is a P-doped polycrystalline silicon film, 24 is a lead titanate-based ferroelectric thin film, 25 is a lower electrode, 26 is an upper electrode, and 27 is an air gap. That is, this infrared detector has an air gap 27 for heat dissipation formed on the Si substrate 20, and a lead titanate-based ferroelectric thin film 24 as a pyroelectric body formed on the air gap 27. Is.
Here, the P-doped polycrystalline silicon film 23 is used as a base layer for forming the lead titanate-based ferroelectric thin film 24.

[0004]

The conventional ferroelectric device is constructed as described above. In the device shown in FIG. 9, as described above, in order to increase the sensitivity of the device, Mg is used.
A cavity 1 for heat dissipation by etching the O single crystal substrate 10
Since 0a is formed and this etching process requires a long time, there is a problem that the manufacturing efficiency is low. For example, when a 0.5 mm-thick MgO single crystal substrate was etched with phosphoric acid, it took about 5 hours. Further, since the MgO single crystal substrate 10 is etched in a taper shape at 45 degrees when forming the cavity 10a,
Since only the pyroelectric body 12 having a smaller area than the entire area of the substrate 10 can be formed, the size of the entire device becomes larger than the size of the pyroelectric body 12, that is, the device can be easily miniaturized. There was a problem that it was not. Also,
Since a part of the MgO single crystal substrate is removed by etching, the substrate cannot be reused, and the MgO single crystal substrate 10 is an expensive substrate, which is also disadvantageous in terms of cost. .

On the other hand, since the device shown in FIG. 10 radiates heat by the air gap 27, it is not necessary to form a through hole in the substrate unlike the device shown in FIG. Can be converted. However, since the P-doped polycrystalline silicon film 23, which is the base layer of the pyroelectric body (lead titanate-based ferroelectric thin film 24), is non-oriented, it is difficult to control the crystal orientation of the pyroelectric body. Since the pyroelectric body (lead titanate-based ferroelectric thin film 24) is formed after forming the air gap 27, it is difficult to form the pyroelectric body in vacuum, and the sensitivity of the detector is sufficiently high. There was a problem that it could not be increased. Also, the air gap 2
Since the step of forming a phosphosilicate glass (PSG) film and the step of removing the same are required for forming No. 7, the manufacturing work becomes complicated and the manufacturing efficiency is low.

The present invention has been made to solve the above problems, and is a small-sized ferroelectric element which is low in cost and excellent in heat dissipation, and a ferroelectric element which can be manufactured in a short time. It aims at providing the manufacturing method of.

Still another object of the present invention is to provide a highly sensitive and low cost ferroelectric device. Still another object of the present invention is to provide a small-sized ferroelectric element having high sensitivity, low cost, and excellent heat dissipation, and a method of manufacturing the ferroelectric element which can be manufactured in a short time. To aim.

[0008]

In a ferroelectric element according to the present invention, a first electrode layer is bonded to a first region of the substrate and a second electrode layer is bonded to a second region of the substrate. In a ferroelectric element provided with the ferroelectric film described above, a metal oxide layer is formed on the surface of the substrate, and the ferroelectric film is formed as an island pattern in a predetermined region on the surface of the metal oxide layer. In addition, a void layer having an area slightly larger than that of the island-shaped pattern is formed in a region located directly below the island-shaped pattern in the upper layer portion of the substrate.

Further, in the ferroelectric element according to the present invention, the first electrode layer is bonded to the first region on the substrate and the second electrode layer is formed on the substrate.
In a ferroelectric element having a ferroelectric film in which a second electrode layer is bonded to the area of, a metal oxide layer is formed on the surface of the substrate, and the ferroelectric film is formed on a predetermined area of the surface of the metal oxide layer. The dielectric film is formed as an island pattern,
A void layer having an area slightly larger than that of the island pattern is formed in a region of the metal oxide layer immediately below the island pattern.

Further, in the ferroelectric element according to the present invention, the first electrode layer is bonded to the first region on the substrate and the second electrode layer is formed on the substrate.
In a ferroelectric element having a ferroelectric film in which a second electrode layer is joined in the region of (10), (10
A metal oxide layer having a NaCl-type crystal structure in which crystals are preferentially oriented on the (0) plane is formed, and the ferroelectric film is formed on the surface of the metal oxide layer.

Further, in the above structure, the ferroelectric film is formed as an island pattern in a predetermined region on the surface of the metal oxide layer, and the ferroelectric film is formed immediately below the island pattern in the upper layer portion of the substrate. It is preferable that a void layer having an area slightly larger than that of the island pattern is formed in the located region.

Further, in the above structure, the ferroelectric film is formed as an island pattern in a predetermined region on the surface of the metal oxide layer, and the ferroelectric film is formed immediately below the island pattern of the metal oxide layer. It is preferable that a void layer having an area slightly larger than that of the island pattern is formed in the located region.

In [0013] the structure, the ferroelectric film is represented by _{Pb x La y Ti z Zr w} O 3, the following (a),
It is preferably composed of a lead titanate-based ferroelectric substance having any one of the compositions (b) and (C).

(A) 0.7 ≦ x ≦ 1, x + y = 1, 0.925 ≦ z ≦ 1, W = 0 (b) x = 1, y = 0, 0.45 ≦ z <1, z + w = 1 (c) 0.75 ≦ x <1, x + y = 1, 0.5 ≦ z <1, z + w = 1 In the above structure, the metal oxide layer is a NiO layer doped with Li. It is preferable that the metal oxide layer is used as the first electrode layer or the second electrode layer.

Next, in the method for manufacturing a ferroelectric element according to the present invention, a metal oxide layer is formed on a substrate, and a first electrode layer and a ferroelectric film are formed on the metal oxide layer in this order. After forming and patterning the ferroelectric film to leave an island-shaped pattern only in a predetermined region on the surface of the first electrode layer, the metal oxide layer and the periphery of the island-shaped pattern of the first electrode layer An etching opening reaching the surface of the substrate is formed in the region, and then a second electrode layer is selectively formed on the island pattern, and then isotropic etching is performed on the substrate through the etching opening. Is performed to form a void layer having an area slightly larger than that of the island-shaped pattern in a region located immediately below the island-shaped pattern in the upper layer portion of the substrate.

Further, in the method for manufacturing a ferroelectric element according to the present invention, a metal oxide layer is formed on a substrate, and a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer. Patterning the ferroelectric film to leave an island-shaped pattern only in a predetermined region on the surface of the first electrode layer, and then forming the metal oxide layer in a peripheral region of the island-shaped pattern of the first electrode layer. Form an etching opening that reaches the surface,
Next, a second electrode layer is selectively formed on the island-shaped pattern, and thereafter, the metal oxide layer is isotropically etched through the etching opening to form the island of the metal oxide layer. It is characterized in that a void layer having an area slightly larger than that of the island-shaped pattern is formed in a region located immediately below the pattern.

Further, the method of manufacturing a ferroelectric element according to the present invention is a high frequency magnetron sputtering method on a substrate or a plasmon excitation MO- using an organic metal complex as a source gas.
Na in which crystals are preferentially oriented on the (100) plane by the CVD method
A metal oxide layer having a Cl type crystal structure is formed, a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer, and the ferroelectric film is patterned to form the first electrode layer.
After leaving an island-shaped pattern only in a predetermined region of the electrode layer surface of, an etching opening reaching the surface of the substrate is formed in a peripheral region of the island-shaped pattern of the metal oxide layer and the first electrode layer, Next, a second electrode layer is selectively formed on the island-shaped pattern, and then the substrate is isotropically etched through the etching opening to form the island-shaped pattern of the upper layer portion of the substrate. It is characterized in that a void layer having an area slightly larger than that of the island pattern is formed in a region located immediately below.

Further, the method of manufacturing a ferroelectric element according to the present invention is a high frequency magnetron sputtering method on a substrate or a plasmon excitation MO- using an organic metal complex as a source gas.
Na in which crystals are preferentially oriented on the (100) plane by the CVD method
A metal oxide layer having a Cl type crystal structure is formed, a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer, and the ferroelectric film is patterned to form the first electrode layer.
After leaving the island-shaped pattern only in a predetermined region of the electrode layer surface of, the etching opening reaching the surface of the metal oxide layer is formed in the peripheral region of the island-shaped pattern of the first electrode layer. A second electrode layer is selectively formed on the island-shaped pattern, and then the metal oxide layer is isotropically etched through the etching opening to form the island-shaped pattern of the metal oxide layer. A void layer having an area slightly larger than that of the island-shaped pattern is formed in a region located immediately below.

Further, in the above structure, when patterning the ferroelectric film, patterning is performed such that the island-shaped pattern has a through hole in the center thereof, and the etching is performed when the etching opening is formed. Aside from the opening for etching, an etching opening reaching the surface of the substrate or the metal oxide layer is formed from the bottom of the through hole of the island-shaped pattern, and the etching opening and the etching opening are provided together. It is preferable to perform isotropic etching.

In the above structure, it is preferable that the metal oxide layer is a NiO layer and the NiO layer is formed in an oxygen excess atmosphere.

[0021]

According to the above-mentioned structure of the ferroelectric element of the present invention, the first electrode layer is bonded to the first region on the substrate,
In a ferroelectric element having a ferroelectric film having a second electrode layer bonded to the second region, a metal oxide layer is formed on the surface of the substrate, and a predetermined region on the surface of the metal oxide layer is formed. The ferroelectric film is formed as an island-shaped pattern, and a void layer having an area slightly larger than the island-shaped pattern is formed in a region located immediately below the island-shaped pattern in the upper layer portion of the substrate. As a result, the heat dissipation is improved by the void layer, and the void layer has substantially the same area as the island pattern of the ferroelectric film.
The element area on the substrate becomes substantially equal to the area of the ferroelectric film pattern, and the element can be downsized. Further, by using a substrate made of a low-cost material as the substrate, it is possible to reduce the cost of the device.

Further, according to the structure of the ferroelectric element of the present invention described above, the first electrode layer is bonded to the first region of the substrate and the second electrode layer is bonded to the second region of the substrate. In a ferroelectric element provided with the ferroelectric film described above, a metal oxide layer is formed on the surface of the substrate, and the ferroelectric film is formed as an island pattern in a predetermined region on the surface of the metal oxide layer. Since the void layer having a slightly larger area than the island pattern is formed in a region located directly below the island pattern of the metal oxide layer, the void layer improves heat dissipation. At the same time, since the void layer has substantially the same area as the island-shaped pattern of the ferroelectric film, the element area on the substrate becomes almost equal to the area of the ferroelectric film pattern, and the element can be miniaturized. You can Further, by using a substrate made of a low-cost material as the substrate, it is possible to reduce the cost of the device.

Further, according to the structure of the ferroelectric element of the present invention described above, the first electrode layer is bonded to the first region of the substrate and the second electrode layer is bonded to the second region of the substrate. In a ferroelectric element provided with the above-mentioned ferroelectric film, a metal oxide layer having a NaCl type crystal structure in which crystals are preferentially oriented on the (100) plane is formed on the surface of the substrate, and the surface of the metal oxide layer is formed. By forming the ferroelectric film on the substrate, the lattice constant of the metal oxide layer and the ferroelectric film is matched regardless of the constituent material of the substrate, and the ferroelectric film is formed. Has a high crystal orientation ratio with respect to its polarization axis, the c-axis. Therefore, it is possible to realize a high-sensitivity element at low cost by using a low-cost material as the substrate.

As a preferred example of the structure, the ferroelectric film is formed as an island-shaped pattern in a predetermined region on the surface of the metal oxide layer, and the island-shaped pattern of the upper layer portion of the substrate is formed. When a void layer having a slightly larger area than the island-shaped pattern is formed in the region located directly below, the heat dissipation is improved by the void layer, and the void layer serves as the island-shaped pattern of the ferroelectric film. Since the areas are almost the same, the area of the element on the substrate becomes almost equal to the area of the ferroelectric film pattern, and the element can be downsized.

As a preferred example of the structure, the ferroelectric film is formed as an island pattern in a predetermined region on the surface of the metal oxide layer, and the island pattern of the metal oxide layer is formed. When an air gap layer having a slightly larger area than the island pattern is formed in the region immediately below, the heat dissipation is improved by the air gap layer, and the air gap layer serves as the island pattern of the ferroelectric film. Since the areas are almost the same, the area of the element on the substrate becomes almost equal to the area of the ferroelectric film pattern, and the element can be downsized.

As a preferable example of the above-mentioned constitution,
Dielectric film is Pb_xLa_yTi_zZr_wO ₃Represented by
Strong lead titanate system with any of (a), (b) and (C) composition
If it is made of a dielectric material, it improves the crystal orientation.
It is effective in the above.

(A) 0.7 ≦ x ≦ 1, x + y = 1, 0.925 ≦ z ≦ 1, W = 0 (b) x = 1, y = 0, 0.45 ≦ z <1, z + w = 1 (c) 0.75 ≦ x <1, x + y = 1, 0.5 ≦ z <1, z + w = 1 Further, as a preferred example of the above structure, the metal oxide layer is a NiO layer in which Li is doped. And when the metal oxide layer is used as the first electrode layer or the second electrode layer, the first electrode layer or the second electrode layer can be omitted, and a further element It is effective for downsizing and cost reduction.

Next, according to the above-described method for manufacturing a ferroelectric element of the present invention, a metal oxide layer is formed on a substrate, and a first electrode layer and a ferroelectric film are formed on the metal oxide layer. The ferroelectric film is formed in this order and is patterned by patterning the ferroelectric film.
After leaving an island-shaped pattern only in a predetermined region of the electrode layer surface of, an etching opening reaching the surface of the substrate is formed in a peripheral region of the island-shaped pattern of the metal oxide layer and the first electrode layer, Next, a second electrode layer is selectively formed on the island-shaped pattern, and then the substrate is isotropically etched through the etching opening to form the island-shaped pattern of the upper layer portion of the substrate. By forming a void layer having an area slightly larger than the island-shaped pattern in a region located immediately below, a ferroelectric element excellent in heat dissipation and small in size, which is configured by using the low-cost substrate, can be efficiently used. It can be manufactured.

Further, according to the method for manufacturing a ferroelectric element of the present invention described above, a metal oxide layer is formed on a substrate, and a first electrode layer and a ferroelectric film are formed on the metal oxide layer. Sequentially, and patterning the ferroelectric film to form the first
After leaving the island-shaped pattern only in a predetermined region of the electrode layer surface of, the etching opening reaching the surface of the metal oxide layer is formed in the peripheral region of the island-shaped pattern of the first electrode layer. A second electrode layer is selectively formed on the island-shaped pattern, and then the metal oxide layer is isotropically etched through the etching opening to form the island-shaped pattern of the metal oxide layer. By forming a void layer having an area slightly larger than the island-shaped pattern in a region located immediately below, a ferroelectric element with excellent heat dissipation and small size, which is configured by using the low-cost substrate, is formed. It can be manufactured efficiently. Moreover, since it is not necessary to perform etching on the substrate, the degree of freedom in selecting the material for the substrate is increased.

Further, according to the above-described method for manufacturing a ferroelectric element of the present invention, a crystal is formed on the (100) plane on the substrate by a high frequency magnetron sputtering method or a plasmon excitation MO-CVD method using an organic metal complex as a source gas. Form a metal oxide layer having a preferentially oriented NaCl type crystal structure, form a first electrode layer and a ferroelectric film on the metal oxide layer in this order, and pattern the ferroelectric film. After leaving the island-shaped pattern only in a predetermined region of the surface of the first electrode layer, an etching opening reaching the surface of the substrate is formed in the peripheral region of the island-shaped pattern of the metal oxide layer and the first electrode layer. Then, a second electrode layer is selectively formed on the island pattern, and then the substrate is isotropically etched through the etching opening to form an upper layer of the substrate. By forming a void layer having an area slightly larger than that of the island-shaped pattern in a region immediately below the island-shaped pattern, a high-sensitivity and small-sized ferroelectric substance formed by using the low-cost substrate described above. The element can be manufactured efficiently.

Further, according to the above-mentioned constitution of the present invention, a NaCl type crystal whose crystal is preferentially oriented on the (100) plane is formed on the substrate by a high frequency magnetron sputtering method or a plasma excited MO-CVD method using an organic metal complex as a source gas. A metal oxide layer having a crystalline structure is formed, a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer, and the ferroelectric film is patterned to form the first electrode layer. After leaving the island-shaped pattern only in a predetermined region of the surface, an etching opening reaching the surface of the metal oxide layer is formed in the peripheral region of the island-shaped pattern of the first electrode layer,
Next, a second electrode layer is selectively formed on the island-shaped pattern, and thereafter, the metal oxide layer is isotropically etched through the etching opening to form the island of the metal oxide layer. By forming a void layer having a slightly larger area than the island-shaped pattern in a region located immediately below the pattern, a highly sensitive and small ferroelectric element constituted by using the low-cost substrate can be efficiently used. Can be manufactured. Also,
Since it is not necessary to etch the substrate, the degree of freedom in selecting the material for the substrate is increased.

In particular, in any of the above manufacturing methods,
Since it is not necessary to perform etching on the substrate so that a through hole is formed in the substrate, the manufacturing time can be greatly shortened as compared with the conventional case.

As a preferred example of the above structure, when patterning the ferroelectric film, patterning is performed so that the island-shaped pattern has a through hole at the center thereof, and when the etching opening is formed, Separately from the etching opening, an etching opening reaching the surface of the substrate or the metal oxide layer from the bottom of the through hole of the island pattern is formed, and through this etching opening and the etching opening When the isotropic etching is performed, the etching time can be shortened and the manufacturing time can be further shortened.

As a preferred example of the above structure, when the metal oxide layer is a NiO layer and the NiO layer is formed in an oxygen excess atmosphere, the NiO layer functions as a P-type semiconductor layer. The ferroelectric element can be manufactured without forming the electrode layer. Therefore, a further miniaturized ferroelectric element can be manufactured in a shorter time.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a structure of a ferroelectric element in which two ferroelectric film patterns are provided side by side on a substrate according to a first embodiment of the present invention at a predetermined interval. (Thermal expansion coefficient 18 × 10 ^-6 ℃ ^-1 , thickness 5
00 μm) 101 surface with (100) plane preferentially oriented N
An MgO thin film 102 having an aCl type crystal structure is arranged, a lower electrode 103 made of a Pt thin film is arranged on the surface of the MgO thin film 102, and a specific portion of the lower electrode 103 is Pb.
_The ferroelectric film 104 made of _0.9 La _0.1 Ti _0.975 O ₃ is covered with the upper electrode 108 made of a Ni—Cr thin film on the surface of the ferroelectric film 104. 105 is an etching hole, and the void layer 110 is this etching hole 1
It was formed through 05. 106, 107,
109 is a protective resin layer made of photosensitive polyimide,
A resin layer 109 protects the upper electrode 108. Here, the void layer 110 is provided in order to prevent heat from the ferroelectric film 104 from being dispersed during operation.

2 and 3 are cross-sectional views and plan views showing the steps of manufacturing the ferroelectric element shown in FIG. In these figures, the same reference numerals as in FIG. 1 indicate the same or corresponding parts. The manufacturing process of the ferroelectric element of this embodiment shown in FIG. 1 will be described below with reference to FIGS.

First, the stainless metal substrate 101 (see FIG. 3)
(a)) on the plasma-excited MO-CVD film forming device,
As a base layer, a MgO thin film 102 having a NaCl-type crystal structure in which crystals are preferentially oriented on a (100) plane having a thickness of 0.2 μm is formed (FIGS. 2 (a) and 3 (b)). FIG. 4 is a diagram schematically showing the configuration of the plasma-enhanced MO-CVD film forming apparatus used in this step, in which 41 is a reaction chamber, 42 are two electrodes arranged in parallel, and 43 is an exhaust gas. System, 45 is a high frequency power source, 46 is a raw material vaporization container, 47
Is a carrier gas cylinder, 48 is a reaction gas cylinder, and 49 is a substrate heating heater. Here, this step will be described in more detail with reference to this drawing. The stainless steel substrate 101 was held by bringing one side surface of the electrode 42 into close contact with the ground side electrode, and heated to 600 ° C. by the substrate heater 49. On the other hand, magnesium acetylacetonate (Mg (C ₅ H ₇ O ₂ ) ₂ ) was placed in the raw material vaporization container 46 and heated using an oil bath maintained at 190 ° C., and vapor of magnesium acetylacetonate vaporized by this heating. To
Carrier gas (nitrogen) having a flow rate of 10 ml / min was used to flow from the carrier gas cylinder 47 into the reaction chamber 41. In addition, oxygen gas as a reaction gas was caused to flow from the reaction gas cylinder 48 at a rate of 12 ml / min, and was introduced into the reaction chamber 41 through a blow nozzle. At this time, the inside of the reaction chamber 41 was vacuum-exhausted from the exhaust system 43 to maintain a vacuum degree of 7.90 Pa. In this state, 13.56 is applied to the RF side electrode of the electrode 42.
Applying a high frequency of 400W at MHz for 10 minutes,
Plasma is generated between the F side electrode and the ground side electrode,
On one surface of the stainless steel substrate 101, Na in which crystals are preferentially oriented on a (100) plane having a thickness of 0.2 μm as a base layer
An MgO thin film 102 having a Cl type crystal structure was formed. During this film formation, the substrate 101 is rotated by 120 rpm by the substrate rotation motor.
It was rotated at a speed of m.

Next, the MgO thin film 10 as the above-mentioned underlayer.
Lower electrode 10 composed of a Pt thin film having a thickness of 0.2 μm on the second electrode 10
3 is formed (FIGS. 2B and 3C). Here, the Pt thin film 103 is formed so that crystals are preferentially oriented on the (100) plane. (10) on the MgO thin film 102 of the NaCl type crystal structure in which crystals are preferentially oriented on the (100) plane
The Pt thin film 103 in which crystals are preferentially oriented on the (0) plane is formed by
For example, by a high frequency magnetron sputtering method, a mixed gas of Ar (95%) and oxygen (5%) is used as a sputtering gas, the substrate temperature is 600 ° C., the gas pressure is 0.5 Pa, and the high frequency input power density is 2.5 W / cm ² (13.56 MH
The film forming conditions described in z) are used. With such a method, a film having a thickness of 0.2 μm can be obtained with a film forming time of 1 hour.

Next, the lower electrode 10 made of the Pt thin film.
On 3, a ferroelectric film 104 made of _{Pb 0.9 La 0 .1 Ti 0.975 O} 3 having a thickness of 3 [mu] m (FIG. 2 (c), the Figure 3
(d)). The ferroelectric film 104 is formed using, for example, a high frequency magnetron sputtering device. Specifically, the substrate is attached to a stainless steel substrate holder, and Pb
A mixture of O, La ₂ O ₃ and TiO ₂ powders (powder mixing ratio was PbO in excess of 20 mol% with respect to the film composition) was placed in a copper dish as a target, and Ar (90) was used as a sputtering gas. %) And oxygen (10%) mixed gas, the substrate temperature is 600 ° C., the gas pressure is 0.9 Pa, and the high frequency input power density is 2.0 W / cm ² (13.56 MHz).
It is performed under the sputter film forming conditions described above.

FIG. 5 shows MgO in which crystals are preferentially oriented on the (100) plane on a stainless metal substrate by the method described above.
X-ray diffraction of a sample obtained by forming a lower electrode 103 made of a thin film 102 and a Pt thin film in this order, and further forming a ferroelectric film made of Pb _0.9 La _0.1 Ti _0.975 O ₃ by the high frequency magnetron sputtering method. It is a pattern. From this X-ray diffraction pattern, the c-axis orientation rate α of this sample
The (%) defined by equation (1), calculation of the value, c-axis orientation rate alpha (%) is 94%, Pb _{0. 9} La
_The ferroelectric film having the composition of _0.1 Ti _0.975 O ₃ was preferentially oriented in the c-axis direction which is the polarization axis.

[0041]

[Equation 1]

Here, I (001), I (100), I
(101), I (111) and I (110) are (001), (100), (101), (111) and
Indicates the intensity of (110) reflection.

Next, the ferroelectric film 104 made of Pb _0.9 La _0.1 Ti _0.975 O ₃ is patterned (FIG. 2 (d),
Figure 3 (e)). This patterning is performed by chemical etching with hydrofluoric nitric acid (required time: 10 minutes) or by sputter etching using Ar gas (required time: 90 minutes).

Next, patterning of the Pt thin film 103 and the MgO thin film 102 as the lower electrode and formation of the etching hole 105 are performed by sputter etching (time required 12 hours).
0 minutes) simultaneously (FIG. 2 (e), FIG. 3 (f)).

Next, the ferroelectric film 10 made of Pt thin film 103 and Pb _0.9 La _0.1 Ti _0.975 O ₃ as the lower electrode.
4 and the entire back surface of the substrate 101 are coated with resin layers 106 and 107 made of photosensitive polyimide by spin coating, and then the resin layer 106 is formed by Pt by photolithography.
The thin film 103 and the ferroelectric film 104 are patterned so as to cover the periphery thereof, and further cured (see FIG. 2 (f) and FIG. 3).
(g)).

Next, a Ni-Cr thin film having a film thickness of 100 nm is formed by the DC-sputtering method, and this is patterned by the photolithography method to form the upper electrode 10.
After forming 8 (FIGS. 2 (g) and 3 (h)), a photosensitive polyimide film is formed and patterned to form an upper electrode protection layer 109 (FIGS. 2 (h) and 3 (h)). (i)).

Finally, the etching hole 1 is formed on the substrate 101.
Etching is performed through 05 to form the void layer 110 (FIG. 2 (i)). This etching is performed by using a 30 wt% ferric chloride (FeCl ₃ ) aqueous solution as an etchant, heating the substrate to 55 ° C., applying ultrasonic waves, and setting the etching time to 15 to 20 minutes.

Thus, in this embodiment, the plasma excitation M
By the O-CVD method, (10
A MgO thin film 102 having a NaCl-type crystal structure in which crystals are preferentially oriented on the (0) plane is formed, and on this MgO thin film 102, for example, a high frequency magnetron sputtering method is used (10
A Pt thin film 103 (lower electrode) in which crystals are preferentially oriented on the (0) plane is formed, and Pb _0.9 La _0.1 Ti _0.975 is formed on the Pt thin film 103 in which crystals are preferentially oriented on the (100) plane by using, for example, a high frequency magnetron sputtering method. A ferroelectric film 104 made of O ₃ is formed, and Pb _0.9 thus obtained is obtained.
Since the ferroelectric element was formed using the ferroelectric film 104 made of La _0.1 Ti _0.975 O ₃ , the MgO thin film 102 (P
It has been attempted matching of lattice constants between the ferroelectric film 104 and t thin film 103) consisting of _{Pb 0.9 La 0.1 Ti 0.975 O 3} , a ferroelectric film 1 made of Pb _0.9 La _0.1 Ti _0.975 O ₃
No. 04 has a high crystal orientation ratio with respect to the c-axis which is its polarization axis, and a highly sensitive ferroelectric element can be realized by using the stainless steel substrate 101 substrate. Therefore, it is possible to obtain a highly sensitive ferroelectric element at low cost. In addition, a gap that dissipates (dissipates) heat of the ferroelectric film 104 only by performing etching for removing a part of the upper layer portion of the substrate 101 without performing etching for penetrating the substrate as in the related art. Since the layer 110 can be formed, a highly sensitive ferroelectric element in which deterioration of the ferroelectric film 104 due to heat generation is prevented can be manufactured in a short time. In addition, the void layer 110
Is obtained by etching and removing a region of the substrate, which is slightly larger than the area of the ferroelectric film 104 patterned in an island shape, through the etching hole 115. Unaffected by
The area is approximately equal to the pattern area of the ferroelectric film 104, and the element can be downsized. In addition, Ni-C
r upper electrode 108 or ferroelectric film 10 made of a thin film
4 is not damaged by the etching for forming the void layer 110, it is not always necessary to provide the electrode protection layer 109. When the upper electrode protection layer 109 is not provided, the heat capacity of the ferroelectric film 104 can be reduced, which is effective in increasing the sensitivity of the thermal element. In patterning the ferroelectric film 104,
Although the ferroelectric film 104 was patterned so as to form an island pattern having a through hole in the central portion thereof, and the etching hole 105 was also formed in the central portion of the island pattern, the central portion of the island pattern was formed. It is not always necessary to form the etching hole 105, and the M around the island pattern is formed.
Using only the etching holes 105 formed in the gO thin film 102 and the Pt thin film 103 (lower electrode), the void layer 1
10 can be formed. When the etching hole 115 is provided in the central portion of the island pattern as in the present embodiment, the etching time required for forming the void layer 110 can be shortened and the manufacturing efficiency can be improved as compared with the case where the etching hole 115 is not provided.

Example 2 In this example, Tables 1 to 4 show
As shown, the material of the substrate, the material of the underlayer and the film formation method, and
And the ferroelectric material different from that of the first embodiment.
Of the same structure as the ferroelectric element of Example 1 shown in FIG.
A ferroelectric element was formed. The substrate has a substrate thickness of 50.
In addition to a 0 μm stainless metal substrate, a 500 μm thick
Gnesia (MgO) polycrystalline substrate, (100) Si single crystal substrate
A plate and a Cu metal substrate were used. And these various
Excitation with Organometallic Complex as Raw Material Gas on Substrate
MO-CVD method or high frequency magnetron sputtering method
Use of NaCl type crystal with crystals preferentially oriented on (100) plane
Form a thin film of MgO or NiO with a crystalline structure
And a thin dielectric composed of MgO or NiO.
Plasma-excited MO-CVD method or high-frequency magnet on the body film
Pb using the Netron sputtering method_0.9La_0.1Ti _0.975 
O₃ Or PbTiO₃ Forming a ferroelectric film consisting of
Was.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

[0053]

[Table 4]

Here, the method for producing a thin film of NiO by the plasma enhanced MOCVD method will be described in detail.
The apparatus used and the basic method are the same as those in the case of forming a thin film of MgO by the plasma enhanced MOCVD method described in the first embodiment. The substrate 101 was preheated to 350 ° C. by the substrate heater 49 using the plasma excited MO-CVD film forming apparatus shown in FIG. On the other hand, nickel acetylacetonate; Ni (C ₅ H ₇ O ₂ ) ₂ H ₂ O was placed in the raw material vaporization vessel 46, and this was heated using an oil bath maintained at 160 ° C., and the nickel acetyl vaporized by this heating was heated. Acetonate vapor was introduced from the carrier gas cylinder 47 into the reaction chamber 41 using a carrier gas (nitrogen) at a flow rate of 35 ml / min. Further, oxygen gas as a reaction gas was flown into the reaction chamber 41 from the reaction gas cylinder 48 at a flow rate of 15 ml / min through a blow nozzle. At this time, the inside of the reaction chamber 41 was vacuum-exhausted from the exhaust system 43 to maintain a vacuum degree of 7.90 Pa. In the above state, the RF side electrode is 13.56 MH
By applying a high frequency of 400 W for 10 minutes at z, plasma was generated between the ground side electrode and the preferentially oriented NiO thin film on the (100) plane on one surface of the substrate. During this film formation, the substrate 101 was rotated by a substrate rotation motor at a speed of 120 rpm. Obtained Ni
The film thickness of the O thin film was 0.2 μm.

Next, a method of forming a thin film of MgO by the rf sputtering method will be described in detail. Using a MgO sintered body (purity 99.9%) as a target, the sputtering film formation conditions are as follows: substrate temperature is 600 ° C., sputtering gas is Ar.
(50%) and oxygen (50%) mixed gas at a gas pressure of 0.
7 Pa, high frequency power density 2.5 W / cm ² (1
3.56 MHz) and the film formation time was set to 1 hour. The film thickness was 0.2 μm. Further, when a thin film made of NiO is formed by the rf sputtering method, NiO powder (purity 99.9%) is used as a target, the sputtering film forming conditions are a substrate temperature of 600 ° C., a sputtering gas of Ar
(60%) and oxygen (40%) mixed gas, gas 1.1
Pa, high frequency input power density is 2.5 W / cm ² (13.
56 MHz) and the film formation time was 1.5 hours to form a film. The film thickness was 0.2 μm.

Next, the method of forming the ferroelectric film made of PbTiO ₃ by the plasma excited MO-CVD method will be described in detail. The plasma-enhanced MO-CVD film forming apparatus shown in FIG.
Heated to 0 ° C. On the other hand, lead dipivaloyl methane; Pb (C ₁₁ H ₁₉ O ₂ ) ₂ was placed in the raw material vaporization vessel 46, and the temperature was set to 130 ° C.
It heated using the oil bath hold | maintained at. The other starting material vaporization vessel 46b, tetra - iso - propyl titanate; put _{Ti (i-C 3 H 7} O) 4, was heated using an oil bath kept at 50 ° C.. The vapor of lead dipivaloyl methane and tetra-iso-propyl titanate which have been vaporized by heating in this way is converted into carrier gas cylinder 4
Carrier gas (nitrogen) with a flow rate of 8 to 10 ml / min
Was poured into the reaction chamber 41. Also,
Oxygen gas as a reaction gas was introduced from a reaction gas cylinder 49 into the reaction chamber 41 at a flow rate of 40 ml / min through a blowing nozzle. At this time, the inside of the reaction chamber 41 is evacuated from the evacuation system 43 to 3.90.
The vacuum degree of Pa was maintained. In the above state, RF
100W of high frequency of 400W at 13.56MHz is applied to the side electrode.
By applying the voltage for a minute, plasma is generated between the ground electrode and (100) on one surface of the substrate 101.
A preferentially oriented PbTiO ₃ ferroelectric material was formed on the surface. The film thickness was 3 μm. During this film formation, the substrate 101 was rotated by a substrate rotation motor at a speed of 120 rpm.

When a magnesia polycrystal substrate was used as the substrate, 10 wt% phosphoric acid aqueous solution was used as an etchant in etching for forming the void layer 110, and etching was carried out at 80 ° C. for 55 minutes. When a (100) Si single crystal substrate is used as the substrate, the etching for forming the void layer 110 is 1
A 0 wt% KOH aqueous solution was used as an etchant. When a Cu metal substrate was used as the substrate, ammonia water was used as an etchant in the etching for forming the void layer 110.

(Embodiment 3) FIG. 6 is a cross-sectional view showing the structure of a ferroelectric element in which two patterns of ferroelectric films are provided side by side on a substrate according to a third embodiment of the present invention at predetermined intervals. is there. Crystallized glass substrate (coefficient of thermal expansion 14 × 10 ^-6 ℃ ^-1 ,
(Thickness 500 μm) 601 surface with thickness of 1.5 μm (1
It has a NaCl type crystal structure with preferential orientation in the (00) plane.
A NiO thin film 602 is arranged, a lower electrode 603 made of a Pt thin film is arranged on the surface of the NiO thin film 602, and a specific portion of the lower electrode 603 is covered with a ferroelectric film 604 made of Pb _0.9 La _0.1 Ti _0.975 O ₃ , An upper electrode 608 made of a Ni—Cr thin film is arranged on the surface of the dielectric film 604. Reference numeral 605 denotes an etching hole, and the void layer 610 is formed through this etching hole 605. Reference numerals 606, 607, and 609 denote protective resin layers made of photosensitive polyimide, and 609 denotes a resin layer that protects the upper electrode 608. Here, the void layer 610 is formed on the NiO thin film 602 and is provided to prevent heat from the ferroelectric film 604 from being dispersed during operation.

7 and 8 are cross-sectional views and plan views showing the manufacturing steps of the ferroelectric element shown in FIG. 6 for each step. In these figures, the same symbols as those in FIG. 6 indicate the same or corresponding portions. The manufacturing process of the ferroelectric element will be described below with reference to these drawings. First, on the substrate 601, Na as a base layer, which is preferentially oriented to the (100) plane, is formed.
A NiO thin film 602 having a Cl type crystal structure is formed by a plasma excited MO-CVD film forming apparatus (FIGS. 7 (a) and 8 (b)). The film forming conditions here are the same as in Example 2,
The film thickness was set to 1.5 μm. Next, a lower electrode 603 made of a Pt thin film is formed on the NiO thin film 602 (FIG. 7).
(b), FIG. 8 (c)). The film forming conditions of this Pt thin film (603) were the same as those of Example 1, and the Pt thin film (603) was formed so that crystals were preferentially oriented on the (100) plane. Next, Pb _0.9 La _0.1 Ti was formed on the lower electrode 603 composed of a Pt thin film.
_A ferroelectric film 604 having a composition of _0.975 O ₃ was prepared (FIG. 7).
(c), FIG. 8 (d)). The method of forming the film of the ferroelectric 604 is the same as that of the first embodiment. Next, the ferroelectric film 0016
Patterning No. 04 is performed (FIGS. 7D and 8E).
This patterning was performed by chemical etching or sputter etching as in the case of Example 1. Further, the patterning of the lower electrode 603 made of a Pt thin film and the formation of the etching hole 605 were simultaneously performed by the sputter etching (required time: 35 minutes) as in the case of Example 1 (FIG. 7 (e), FIG. 8 (f)). Next, a resin layer 606 made of a photosensitive polyimide resin was formed on the lower electrode 603 and the ferroelectric 604, and a resin layer 607 made of a photosensitive polyimide resin was applied and formed on the entire back surface of the substrate by spin coating. Next, the resin layer 606 was patterned by a photolithography method so as to have a shape covering the lower electrode 603 and the ferroelectric body 604, and further cured (FIGS. 7 (f) and 8 (g)). Next, N with a film thickness of 100 nm
An upper electrode 608 made of an i-Cr thin film is formed by a DC-sputtering method, patterned by a photolithography method (FIGS. 7 (g) and 8 (h)), and then a photosensitive polyimide film is formed. The upper electrode protective layer 609 was formed by patterning (FIGS. 7 (h) and 8 (i)). Finally, Ni
The O thin film 602 was etched through the etching hole 605 to form the void layer 610 (FIG. 7).
(i)). In this etching, 10 as an etchant
Etching was performed at 80 ° C. using a wt% phosphoric acid aqueous solution.

The ferroelectric element of the present embodiment as described above can obtain the same action and effect as the ferroelectric element of the embodiment 1, and the NiO thin film 602 can be obtained without etching the substrate 601. Ni is etched only on
Since the void layer 610 is formed on the O thin film 602, the substrate 60
A substrate made of a material that is difficult to etch can be used as No. 1, and the degree of freedom in selecting the material of the substrate becomes greater than that of the ferroelectric element of the first embodiment.

When the NiO thin film 602 is formed in an oxygen excess atmosphere, Ni ²⁺ ions of NiO are oxidized by Ni.
^The NiO thin film 602 becomes a P-type semiconductor film because it becomes a ³⁺ ion and a hole is generated to maintain electrical neutrality. In this case, since the NiO thin film 602 can be used as an electrode, a ferroelectric element can be obtained without forming the lower electrode 603, and a more compact ferroelectric element can be manufactured in a shorter manufacturing time. can do. Also,
If Li is doped at the time of forming the NiO thin film 602, N
Since the iO thin film 602 becomes a P-type semiconductor film, a ferroelectric element can be obtained without forming the lower electrode 603 in this case as well, and a smaller ferroelectric element can be manufactured in a shorter manufacturing time. be able to.

(Embodiment 4) In this embodiment, as shown in Tables 5 to 7, the material of the substrate, the material of the underlayer and the film forming method, and the material of the ferroelectric substance are different from those of the embodiment 3. Then, a ferroelectric element having the same structure as the ferroelectric element of Example 3 shown in FIG. 8 was formed. The film forming conditions of the underlayer and the dielectric film are the same as those of the first or second embodiment. As the substrate 601, a crystallized glass substrate having a substrate thickness of 500 μm, a stainless metal substrate, and an alumina sintered body substrate were used.

[0063]

[Table 5]

[0064]

[Table 6]

[0065]

[Table 7]

It should be noted that in the above-mentioned Examples 1 to 4, two substrates are provided on the substrate.
Make sure that the ferroelectric film patterns of
The linear array ferroelectric element described above was explained.
It goes without saying that Ming can be applied to single elements and two-dimensional elements.
Absent. Moreover, in Examples 1 to 4, the ferroelectric film is used.
Pb_0.9La_0.1Ti_0.975O₃Membrane or PbTiO₃ The membrane
However, in the present invention, these Pb_0.9La_0.1Ti_0.975
O₃, PbTiO₃ Other than lead titanate-based compounds
A ferroelectric film made of an electric material can be used. example
If the general formula is Pb_xLa_yTi_zZr_wO₃When (a)
0.7 ≦ x ≦ 1, x + y = 1, 0.925 ≦ z ≦ 1,
 W = 0, (b) x = 1, y = 0, 0.45 ≦
z <1, z + w = 1, or (c) 0.75 ≦ x
<1, x + y = 1, 0.5 ≦ z <1, z + w = 1
Made of lead titanate-based ferroelectrics with either composition
A ferroelectric film can be used. Also, the above-mentioned embodiment
In 1 to 4, Pb was used as the ferroelectric film._0.9La_0.1Ti
_0.975O₃Membrane or PbTiO ₃ Although a membrane was used, in the present invention
Is a ferroelectric material other than the lead titanate-based ferroelectric material (eg,
(Eg, barium titanate-based ferroelectric)
Membranes can be used. Moreover, in the above-mentioned Examples 1 to 4,
Is a stainless steel substrate, a crystallized glass substrate
Plate, single crystal silicon substrate, alumina (Al₂O₃) Sintering
Body substrate, magnesia (MgO) polycrystalline substrate, and Cu
A metal substrate was used, but in the present invention, the surface is
NaCl-type crystal structure in which crystals are preferentially oriented in the (100) plane
A substrate on which a metal oxide layer composed of
If so, use a substrate made of a different material from the substrate
be able to.

[0067]

As described above, according to the ferroelectric element of the present invention, the first electrode layer is bonded to the first region of the substrate and the second electrode layer is bonded to the second region of the substrate. In a ferroelectric element provided with a joined ferroelectric film, a metal oxide layer is formed on the surface of the substrate, and the ferroelectric film is formed as an island pattern in a predetermined region of the surface of the metal oxide layer. Since a void layer having a slightly larger area than the island pattern is formed in a region located directly below the island pattern in the upper layer portion of the substrate, the void layer improves heat dissipation. At the same time, since the void layer has substantially the same area as the island-shaped pattern of the ferroelectric film, the element area on the substrate becomes almost equal to the area of the ferroelectric film pattern, and the element can be miniaturized. You can
Further, by using a substrate made of a low-cost material as the substrate, it is possible to reduce the cost of the device.

Furthermore, according to the ferroelectric element of the present invention, the first electrode layer is bonded to the first region on the substrate, and the second electrode layer is formed on the substrate.
In a ferroelectric element having a ferroelectric film in which a second electrode layer is bonded to the area of, a metal oxide layer is formed on the surface of the substrate, and the ferroelectric film is formed on a predetermined area of the surface of the metal oxide layer. The dielectric film is formed as an island pattern,
Since a void layer having a slightly larger area than the island pattern is formed in a region located directly below the island pattern of the metal oxide layer, the void layer improves heat dissipation and the void layer is formed. Since the area is substantially the same as the island pattern of the ferroelectric film, the area of the element on the substrate becomes substantially equal to the area of the ferroelectric film pattern, and the element can be miniaturized. Further, by using a substrate made of a low-cost material as the substrate, it is possible to reduce the cost of the device.

Further, according to the ferroelectric element of the present invention, the first electrode layer is bonded to the first region on the substrate, and the second electrode layer is bonded to the second region.
In a ferroelectric element in which a ferroelectric film in which a second electrode layer is bonded is provided in the region of (10), (10
Since a metal oxide layer having a NaCl type crystal structure in which crystals are preferentially oriented is formed on the (0) plane and the ferroelectric film is formed on the surface of the metal oxide layer, regardless of the constituent material of the substrate. , The matching of the lattice constant between the metal oxide layer and the ferroelectric film is achieved, and the ferroelectric film has a high crystal orientation ratio to the c-axis which is the polarization axis of the ferroelectric film.
A highly sensitive element can be realized by using a substrate made of a low-cost material as the substrate.

Next, according to the method of manufacturing a ferroelectric element of the present invention, a metal oxide layer is formed on a substrate, and a first electrode layer and a ferroelectric film are formed on the metal oxide layer. The ferroelectric film is sequentially formed, and the island pattern is left only in a predetermined region of the surface of the first electrode layer by patterning the ferroelectric film. Then, the island pattern of the metal oxide layer and the first electrode layer is formed. An etching opening reaching the surface of the substrate is formed in a peripheral region, and then a second electrode layer is selectively formed on the island-shaped pattern, and thereafter, the substrate is isotropic through the etching opening. Etching is performed to form a void layer having an area slightly larger than the island pattern in a region located immediately below the island pattern in the upper layer portion of the substrate, so that the low cost substrate is used. ， Excellent heat dissipation and small size The conductor elements can be manufactured efficiently. Further, since it is not necessary to perform etching for forming a through hole on the substrate, the manufacturing time can be greatly shortened as compared with the conventional case.

Further, according to the method of manufacturing a ferroelectric element of the present invention, a metal oxide layer is formed on a substrate, and a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer. Then, the ferroelectric film is patterned to leave an island-shaped pattern only in a predetermined area on the surface of the first electrode layer, and then the metal oxide is formed in a peripheral area of the island-shaped pattern of the first electrode layer. Forming an etching opening reaching the layer surface,
Next, a second electrode layer is selectively formed on the island-shaped pattern, and thereafter, the metal oxide layer is isotropically etched through the etching opening to form the island of the metal oxide layer. Since a void layer having an area slightly larger than that of the island pattern is formed in a region located immediately below the pattern, it is possible to realize a small ferroelectric element excellent in heat dissipation, which is configured by using the low cost substrate. It can be manufactured efficiently. Moreover, since it is not necessary to perform etching on the substrate, the degree of freedom in selecting the material for the substrate can be increased. Further, since it is not necessary to perform etching for forming a through hole on the substrate, the manufacturing time can be greatly shortened as compared with the conventional case.

Further, according to the method of manufacturing a ferroelectric element of the present invention, a high frequency magnetron sputtering method or a plasmon excitation MO-using an organometallic complex as a source gas on a substrate.
Na in which crystals are preferentially oriented on the (100) plane by the CVD method
A metal oxide layer having a Cl type crystal structure is formed, a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer, and the ferroelectric film is patterned to form the first electrode layer.
After leaving an island-shaped pattern only in a predetermined region of the electrode layer surface of, an etching opening reaching the surface of the substrate is formed in a peripheral region of the island-shaped pattern of the metal oxide layer and the first electrode layer, Next, a second electrode layer is selectively formed on the island-shaped pattern, and then the substrate is isotropically etched through the etching opening to form the island-shaped pattern of the upper layer portion of the substrate. Since the void layer having a slightly larger area than the island pattern is formed in the region located directly below, a highly sensitive and small ferroelectric element constituted by using the low cost substrate can be efficiently manufactured. can do. Further, since it is not necessary to perform etching for forming a through hole on the substrate, the manufacturing time can be greatly shortened as compared with the conventional case.

Further, according to the method for manufacturing a ferroelectric element of the present invention, a high frequency magnetron sputtering method or plasma excited MO using an organometallic complex as a source gas on a substrate.
-N in which crystals are preferentially oriented on the (100) plane by the CVD method
A metal oxide layer having an aCl type crystal structure is formed, a first electrode layer and a ferroelectric film are formed on the metal oxide layer in this order, and the ferroelectric film is patterned to form the first electrode layer. After leaving the island-shaped pattern only in a predetermined region of the electrode layer surface, an etching opening reaching the surface of the metal oxide layer is formed in a peripheral region of the island-shaped pattern of the first electrode layer, and then, A second electrode layer is selectively formed on the island-shaped pattern, and then the metal oxide layer is isotropically etched through the etching opening to form the island-shaped pattern of the metal oxide layer. Since the void layer having a slightly larger area than the island pattern is formed in the region located directly below, a highly sensitive and small ferroelectric element constituted by using the low cost substrate can be efficiently manufactured. can do. Moreover, since it is not necessary to perform etching on the substrate, the degree of freedom in selecting the material for the substrate can be further expanded. Further, since it is not necessary to perform etching for forming a through hole on the substrate, the manufacturing time can be greatly shortened as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a ferroelectric element according to a first embodiment of the present invention.

2A to 2D are cross-sectional views showing a manufacturing process of the ferroelectric element of FIG.

FIG. 3 is a plan view for each step showing the manufacturing process of the ferroelectric element of FIG.

FIG. 4 is a schematic cross-sectional view showing the configuration of a plasma enhanced MO-CVD apparatus used in Examples 1 to 4 of the present invention.

FIG. 5 is a diagram showing a ferroelectric element according to Example 1 of the present invention in which a crystal is preferentially oriented on a (100) plane on a stainless steel metal substrate M.
gO thin film, Pt thin film, and Pb0.9La0.1Ti0.975O3
X of a sample in which a ferroelectric film made of is formed in this order
It is a line diffraction pattern.

FIG. 6 is a sectional view showing the structure of a ferroelectric element according to an example of the present invention.

7A to 7C are cross-sectional views for each process showing the manufacturing process of the ferroelectric element of FIG.

FIG. 8 is a plan view for each step showing the manufacturing process of the ferroelectric element of FIG.

FIG. 9 is a sectional perspective view showing a configuration of a conventional ferroelectric element.

FIG. 10 is a sectional perspective view showing a structure of a conventional ferroelectric element (infrared detector).

[Explanation of symbols]

41 Reaction Chamber 42 Electrode 43 Exhaust System 45 High Frequency Power Supply 46 Vaporizer 47 Carrier Gas Cylinder 48 Reaction Gas Cylinder 49 Substrate Heating Heater 101 Stainless Metal Substrate 102 MgO Thin Film 103 Lower Electrode 104 Pb _0.9 La _0.1 Ti _0.975 O ₃ Ferroelectric Film 105 Etching hole 106 Resin layer 107 Resin layer (rear surface) 108 Upper electrode 109 Upper electrode resin layer 110 Void layer 601 Crystallized glass substrate 602 NiO film 603 Lower electrode 604 Pb _0.9 La _0.1 Ti _0.975 O ₃ ferroelectric film 605 Etching hole 606 Resin layer 607 Resin layer (back surface) 608 Upper electrode 609 Upper electrode protection resin layer 610 Void layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C23F 1/00 G01J 1/02 Y 4/00 G01L 1/16 G01J 1/02 H01L 29/84 A G01L 1/16 37/02 H01L 21/3065 C04B 35/46 H 29/84 35/49 Z 37/02 H01L 21/302 J 41/08 41/08 Z 41/187 41/18 101D 41/22 41 / 22 Z 41/24 A (72) Inventor Jun Tomozawa At 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (13)

[Claims] 1. A ferroelectric element comprising a ferroelectric film having a first electrode layer bonded to its first region and a second electrode layer bonded to its second region on a substrate. In, the metal oxide layer is formed on the surface of the substrate, the ferroelectric film is formed as an island pattern in a predetermined region of the surface of the metal oxide layer, and the island pattern of the upper layer portion of the substrate. 2. A ferroelectric element, characterized in that a void layer having an area slightly larger than that of the island-shaped pattern is formed in a region located directly under the ferroelectric element. 2. A ferroelectric device comprising a substrate, and a ferroelectric film having a first electrode layer bonded to a first region thereof and a second electrode layer bonded to a second region thereof. In, the metal oxide layer is formed on the substrate surface, the ferroelectric film is formed as an island-shaped pattern in a predetermined region of the metal oxide layer surface, and the island-shaped pattern of the metal oxide layer. A ferroelectric element having a void layer having an area slightly larger than that of the island-shaped pattern formed in a region immediately below the ferroelectric element. 3. A ferroelectric element comprising a substrate, and a ferroelectric film in which a first electrode layer is bonded to a first region of the substrate and a second electrode layer is bonded to a second region of the substrate. In the above-mentioned substrate surface, NaCl in which crystals are preferentially oriented on the (100) plane
A ferroelectric element, wherein a metal oxide layer having a type crystal structure is formed, and the ferroelectric film is formed on the surface of the metal oxide layer. 4. The ferroelectric film is formed as an island-shaped pattern in a predetermined region on the surface of the metal oxide layer, and is formed in a region located immediately below the island-shaped pattern in the upper layer portion of the substrate. The ferroelectric element according to claim 3, wherein a void layer having an area slightly larger than that of the island pattern is formed. 5. The ferroelectric film is formed as an island-shaped pattern in a predetermined region of the surface of the metal oxide layer, and is formed in a region located directly below the island-shaped pattern of the metal oxide layer. The ferroelectric device according to claim 3, wherein a void layer having an area slightly larger than the island pattern is formed. 6. The ferroelectric thin film is Pb _x La _y Ti _z.
The ferroelectric element according to claim 3, comprising a lead titanate-based ferroelectric having the composition of any one of (a), (b), and (C) below, which is represented by Zr _w O ₃ . (a) 0.7 ≦ x ≦ 1, x + y = 1, 0.925 ≦ z ≦ 1, W = 0 (b) x = 1, y = 0, 0.45 ≦ z <1, z + w = 1 (c ) 0.75 ≦ x <1, x + y = 1, 0.5 ≦ z <1, z + w = 1 7. The metal oxide layer is a Li-doped NiO layer, and the metal oxide layer is used as the first electrode layer or the second electrode layer.
4. The ferroelectric element according to any one of 3 to 3. 8. A metal oxide layer is formed on a substrate, a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer, and the ferroelectric film is patterned to form the first electrode layer and the ferroelectric film. 1
After leaving an island-shaped pattern only in a predetermined region of the electrode layer surface of, an etching opening reaching the surface of the substrate is formed in a peripheral region of the island-shaped pattern of the metal oxide layer and the first electrode layer, Next, a second electrode layer is selectively formed on the island-shaped pattern, and then the substrate is isotropically etched through the etching opening to form the island-shaped pattern of the upper layer portion of the substrate. A method of manufacturing a ferroelectric element, characterized in that a void layer having an area slightly larger than that of the island pattern is formed in a region located immediately below. 9. A metal oxide layer is formed on a substrate, a first electrode layer and a ferroelectric film are formed in this order on the metal oxide layer, and the ferroelectric film is patterned to form the first electrode layer and the ferroelectric film. 1
After leaving the island-shaped pattern only in a predetermined region of the electrode layer surface of, the etching opening reaching the surface of the metal oxide layer is formed in the peripheral region of the island-shaped pattern of the first electrode layer. A second electrode layer is selectively formed on the island-shaped pattern, and then the metal oxide layer is isotropically etched through the etching opening to form the island-shaped pattern of the metal oxide layer. A method of manufacturing a ferroelectric element, characterized in that a void layer having an area slightly larger than the island-shaped pattern is formed in a region located immediately below. 10. A metal oxide layer having a NaCl-type crystal structure in which crystals are preferentially oriented on a (100) plane by a high frequency magnetron sputtering method or a plasmon excitation MO-CVD method using an organometallic complex as a source gas on a substrate. And forming a first electrode layer and a ferroelectric film on the metal oxide layer in this order, and patterning the ferroelectric film to form an island pattern only in a predetermined region on the surface of the first electrode layer. Of the metal oxide layer and the first electrode layer, an opening for etching reaching the surface of the substrate is formed in a peripheral region of the island-shaped pattern, and then a selective opening is formed on the island-shaped pattern. Second electrode layer is formed, and then the substrate is isotropically etched through the etching opening to form the island-shaped region in a region located immediately below the island-shaped pattern in the upper layer portion of the substrate. A method of manufacturing a ferroelectric element, comprising forming a void layer having an area slightly larger than a pattern. 11. A metal oxide layer having a NaCl-type crystal structure in which crystals are preferentially oriented on the (100) plane is formed on a substrate by a high frequency magnetron sputtering method or a plasmon excitation MO-CVD method using an organic metal complex as a source gas. And forming a first electrode layer and a ferroelectric film on the metal oxide layer in this order, and patterning the ferroelectric film to form an island pattern only in a predetermined region on the surface of the first electrode layer. Of the first electrode layer, an etching opening reaching the surface of the metal oxide layer is formed in a peripheral region of the island-shaped pattern of the first electrode layer, and then a second opening is selectively formed on the island-shaped pattern. An electrode layer is formed, and then, the metal oxide layer is isotropically etched through the etching opening to form the island-shaped pattern in a region located directly below the island-shaped pattern of the metal oxide layer. A method of manufacturing a ferroelectric element, comprising forming a void layer having an area slightly larger than a turn. 12. When patterning the ferroelectric film, patterning is performed so that the island-shaped pattern has a through hole in the center thereof, and when the etching opening is formed, the etching opening is Separately, an etching opening reaching from the bottom of the through hole of the island pattern to the surface of the substrate or the metal oxide layer is formed, and the isotropic etching is performed through both the etching opening and the etching opening. Claims 8 to 11
7. A method for manufacturing a ferroelectric element according to any one of 1. 13. The metal oxide layer is a NiO layer,
The NiO layer is formed in an oxygen excess atmosphere.
1. The method for manufacturing a ferroelectric element according to any one of 1.