JP2003142482A - Method of manufacturing oxynitride film and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a silicon oxynitride film in which permittivity is high, an interface state and fixed charge are reduced, and an increase in film thickness when a high dielectric film is formed on its surface is prevented. SOLUTION: A silicon oxide film is nitrided by using N(<4> S) in a quartet state, which is a ground state of a nitrogen atom radical, more preferably N(<2> D) or N(<2> P) in a double state, which is an excited state of a nitrogen atom radical, to form a silicon oxynitride film in which nitrogen concentration is high in the vicinity of the surface and low in the vicinity of the interface on the side of a substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an oxynitride film and a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art With the miniaturization of silicon semiconductor integrated circuits, MOS (Metal Oxide Semiconductor)
The size of the (uctor) type semiconductor element has been miniaturized. I
TRS (International Technology)
odyy Roadmap for Semiconductor
According to the 2000 update version of
After 2005, the equivalent film thickness of silicon oxide film (Equiva
Lent Physical Oxide Thick
A gate insulating film having a thickness of 1.5 nm or less is required in terms of “ness: abbreviated as EOT” hereinafter.

In order to suppress the leak current in the gate insulating film having a thickness of 1.5 nm or less, a SiO ₂ film or a silicon oxynitride film having a nitrogen concentration lower than 20% (hereinafter referred to as S
(It is called an iON film) is insufficient. Therefore, SiON
A method of increasing the nitrogen concentration in the film to increase the dielectric constant, or a high-dielectric film (hereinafter referred to as a high-k film) that originally has a high dielectric constant, such as a metal oxide or a metal silicate, as a gate insulating film. The method used is proposed.

Further, since the MOS type semiconductor element of the logic integrated circuit is required to have high current driving capability as well as to suppress leak current, it is essential to increase the mobility. Therefore, the SiON film and the high-k film used as the gate insulating film are required to reduce the interface state density and the fixed charge density to suppress the decrease in mobility.

In order to achieve such characteristics as the gate insulating film, the conventional SiON film forming method is S
A method of oxynitriding a SiO ₂ film formed on the surface of an i substrate with NO gas or a method of nitriding with a nitrogen plasma has been used.

However, in the method of oxynitriding the SiO ₂ film with NO gas, nitrogen atoms diffuse into the vicinity of the interface between the SiO ₂ film and the Si substrate, so that an interface state or fixed charge is generated and mobility is lowered. There is. As a result, M
The driving force of the OS type semiconductor element is reduced. further,
In this method, there is a problem that the nitrogen concentration in the SiO ₂ film is saturated with insufficient nitrogen concentration and is not sufficiently nitrided. As a result, the required dielectric constant cannot be achieved.

On the other hand, it has been reported that the method of nitriding the SiO ₂ film with nitrogen plasma (hereinafter referred to as plasma nitriding) can suppress the nitrogen concentration near the SiO ₂ film / Si substrate interface with a thickness of about several nm. (M. Togo,
K. Watanabe, T .; Yamamoto, N.M. I
Karashi, K .; Shiba, T .; Tatsum
i, H.I. Ono, T. Mogami, 2000
Symp. on VLSI Tech. p. 11
6).

However the nitrogen concentration of SiO ₂ film in the plasma nitridation of SiO ₂ film has a problem of not being sufficiently nitrided becomes saturated remains insufficient. Furthermore, if the thickness is about 1.5 nm or less, which is the thickness required for the gate insulating film in the future, nitrogen atoms will reach the SiO ₂ film / Si substrate interface even in plasma nitriding, thus preventing generation of the interface state and fixed charges. It is not possible.

When a high-k film is used as the gate insulating film, in order to prevent deterioration of the interface characteristics due to direct contact between the metal oxide and the Si substrate, SiON is used as a buffer layer between the metal oxide and the Si substrate. Forming a film is being considered.

However, when the SiON film is used as the buffer layer, if the nitrogen concentration is insufficient, sputtering, vapor deposition, laser ablation, chemical vapor deposition (CVD) or O ₂ annealing atmosphere at the time of forming the metal oxide causes There is a problem that EOT increases, or oxygen atoms and nitrogen atoms diffuse into the Si substrate and the metal oxide.

[0011]

[Problems to be Solved by the Invention]
The SiON film formed by plasma nitridation of the iO ₂ film has a (1) insufficient nitrogen concentration in the film, and therefore has a too low dielectric constant for use in a device having a small EOT required in the future, (2) If the thickness is about 1.5 nm or less, SiO ₂
Nitrogen diffuses at the film / Si substrate interface to generate interface states and fixed charges. (3) Since the nitrogen concentration in the film is insufficient, the SiON film is oxidized when the high-k film is formed on the film surface. There is a problem that the EOT film thickness increases or oxygen atoms and nitrogen atoms diffuse into each other in the Si substrate and the metal oxide.

The present invention has been made to solve these problems, and nitrogen can be introduced at a high concentration only in the vicinity of the surface of the SiO ₂ film, and the above problems can be solved. Provided are a method for manufacturing an oxynitride film and a method for manufacturing a semiconductor device.

[0013]

In order to achieve the above object, the present invention provides an insulating source containing a silicon atom and an oxygen atom for a nitriding source gas containing a nitrogen atom radical in a doublet state or a quartet state. A method for producing an oxynitride film, which comprises supplying the film to the surface of the film and nitriding the surface of the insulating film.

Further, according to the present invention, the nitriding source gas containing nitrogen atom radicals in the doublet state or the quartet state is applied to the surface of the insulating film layer containing silicon atoms and oxygen atoms formed on the silicon layer. And nitriding the surface of the insulating film, and forming a metal oxide film or a solid solution film of metal oxide and silicon oxide on the nitrided surface of the insulating film. A method of manufacturing a semiconductor device is provided.

At this time, the nitriding source gas containing nitrogen atom radicals in the doublet state can be generated by irradiating light to a gas of a molecule having a nitrogen atom to give energy of 12.14 eV or more. preferable.

In addition, a nitriding source gas containing nitrogen atom radicals in the doublet state is generated by irradiating plasma of a gas of molecules having nitrogen atoms with light to give energy of 5.92 eV or more. Is preferred.

Further, it is preferable to generate a nitriding source gas containing nitrogen atom radicals in the doublet state by irradiating a gas of a molecule having a nitrogen atom with light to give energy of 14.53 eV or more. .

In addition, a nitriding source gas containing nitrogen atom radicals in the doublet state is generated by irradiating plasma of a gas of molecules having nitrogen atoms with light to give energy of 8.31 eV or more. Is preferred.

Further, it is preferable that the nitriding source gas has a partial pressure of a gas of a molecule having a nitrogen atom of 133.3 Pa (Pascal) or less.

Further, it is preferable to generate a nitriding source gas containing nitrogen atom radicals in the quartet state by irradiating a gas of a molecule having a nitrogen atom with light to give energy of 9.76 eV or more. .

In addition, a nitriding source gas containing nitrogen atom radicals in the quartet state is generated by irradiating plasma of a gas of molecules having nitrogen atoms with light to give energy of 3.54 eV or more. Is preferred.

The nitriding source gas preferably has a partial pressure of gas containing nitrogen atoms in the molecule of 1333 Pa (Pascal) or less.

The gas of the molecule having the nitrogen atom is N ₂ , NCl ₃ , NF ₃ , NH ₃ , NO, NO ₂ or N _2.
It is preferable to contain any one of O.

The metal oxide film is made of Ta._TwoO₆, T
iO_Two, ZrO_Two, HfO_Two, La _TwoO_Three, Gd
_TwoO_Three, Sc_TwoO_Three, Pr_TwoO_Three, Nd_TwoO_Three, Sm_Two
O_Three, Eu _TwoO_Three, Dy_TwoO_Three, Ho_TwoO_Three, Yb_TwoO
_Three, Y_xO_yOf the metal oxide and
Zr is a solid solution film with recon oxide_xSi_yO_z, Hr_x
Si _yO_z, La_xSi_yO_z, Ti_xSi_yO_z, L
a_xAl_yO_z, Zr_xTi _yO_z, Sn_xTi
_yO_z, Sr_xZr_yO_z, Ba_xZr_yO_zWhich of
It is preferable to contain

In the present invention, N in a quartet state, which is a ground state of a nitrogen atom radical having higher reactivity than N ₂ ^* (excited state of nitrogen molecule, hereinafter referred to as nitrogen molecule radical).
⁽⁴ S), more preferably by nitriding the surface of the SiO ₂ film by using the ^{N (2} D), or ^{N (2} P) of the doublet state its excited state, in the vicinity of the surface of the SiO ₂ film Only high concentration can be nitrided.

As a result, nitrogen atoms are not diffused at the interface of the SiO ₂ film / Si interface, the interface states and fixed charges can be suppressed, and the nitrogen concentration of the SiON film can be made high, so that the dielectric constant can be increased. Can be increased.
Therefore, the SiON film having a small EOT can be applied as the gate insulating film.

When the metal oxide film is formed on the surface of the SiON film, the growth of the SiON film due to the oxidizing atmosphere is suppressed, the increase of the EOT of the high-k film as a whole is suppressed, and the nitrogen atoms of the SiON film are reduced. Since it is densified at a high concentration, it is possible to prevent oxygen and nitrogen from mutually diffusing into the Si substrate or the metal oxide film.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. The present invention is not limited to the following embodiments and can be variously devised and used.

(First Embodiment) FIG. 1 shows an S according to the present invention.
It is sectional drawing of the manufacturing apparatus of an iON film.

In this manufacturing apparatus, a housing 202 is provided with a silicon substrate 101 mounted thereon and a heater 202 capable of applying heat thereto. Supply pipes 203, 206 ₁ , 20 for supplying a nitriding source gas for nitriding the surface of the silicon substrate 101 to the housing 201.
6 ₂ and 206 ₃ are provided. Of these, the supply pipe 203 is provided on the wall portion so that gas can be supplied in a direction parallel to the surface of the silicon substrate 101, and the remaining supply pipes 206 ₁ , 206 ₂ , and 206 ₃ are the silicon pipe ₁₀ and the remaining supply pipes.
It is provided on the upper part so that the gas can be supplied in a direction perpendicular to the surface of 1. In addition, the supply pipes 203, 206 ₁ ,
206 The _2, 206 _3, respectively discharge electrodes 204,2
07 _{1, 207} 2, 207 ₃ are provided, so that it can be a plasma state by applying energy to the gas to be supplied.

Here, the gas supply pipes 206 ₁ , 206 ₂ ,
206 ₃ The gas from the upper portion is provided over so that it can supply to the surface of the silicon substrate 101, particularly when supplying a nitriding source gas, longer mean free path of the radicals to set a low pressure This is so that the radicals reach the surface of the silicon substrate 101 as much as possible before they collide with other molecules or atoms.

Further, the gas supply pipe 203 is connected to the silicon substrate 1
01 is provided on the wall so that the gas can be supplied from the lateral direction in order to form an oxide film in the substrate surface with good uniformity, especially when supplying an oxygen source gas for oxidation. Is.

An irradiation port 208 for irradiating the gas supplied to the surface of the silicon substrate 101 with light for giving energy to the gas is provided on the wall of the housing 201.

Further, exhaust ports 205 ₁ and 205 ₂ for exhausting unnecessary gas are provided on the floor of the casing 201.

Next, a method of locally nitriding the surface of the SiO ₂ film formed on the silicon substrate using this apparatus will be described.

First, the silicon substrate 101 is mounted on the heater 202 provided in the housing 201 and heated.

Next, on the surface of the silicon substrate 101,
Oxide source gas such as O ₂ , O ₃ , H ₂ O, or H ₂ O ₂ is mainly supplied from the supply pipe 203 to form a SiO ₂ film. At this time, the discharge electrode 204 may be discharged to a plasma state.

Next, this SiO_TwoFilm-formed silicon
N on the surface of the substrate 101_Two, NH _Three, NCl_Three, NF
_Three, NO, N_TwoO or NO_TwoNitrogen atom in the molecule such as
Supply gas 206 having gas₁, 206_Two, 206_ThreeFrom
Supply. At this time, the discharge electrode 207₁, 207_Two, 20
7_ThreeMay be discharged into a plasma state.

Next, the supply pipes 206 ₁ , 206 ₂ , 206
Excitation light 209 is introduced from the light irradiation port 208 into the gas ejected from the tip of No. ₃ to supply energy near the surface of the silicon substrate 101. At this time, in the nitriding of the SiO ₂ surface, the nitrogen atom radical N ( ² D) in the doublet state is excited by the excitation light 209 emitted from the light irradiation port 208.
N ( ² P) or a nitrogen atom radical N ( ⁴
S) is generated. In this way, a nitriding source gas containing nitrogen atom radicals in the doublet state or nitrogen atom radicals in the quartet state is introduced.

Thus, the surface of the SiO ₂ film formed on the silicon substrate 101 can be locally nitrided.

At this time, the supply pipes 206 ₁ , 206 ₂ , 20
6 ₃ tip, when the width of the excitation light 209 is narrow, excitation light 2
In order to efficiently expose the gas to 09, it is thin like a nozzle. Further, in order to uniformly supply the nitrogen atom radicals to the surface of the silicon substrate 101, the supply pipe 20
A plurality of 6 ₁ , 206 ₂ , and 206 ₃ are provided. The gas in the atmosphere is exhausted via the exhaust port 205.

Next, with reference to FIGS. 2 to 7, description will be given of a method of manufacturing a semiconductor device in which a SiON film is formed by using the apparatus of FIG. 1 and is used as a gate insulating film of an n-type MOS transistor.

First, as shown in FIG. 2, a deep trench 11 for device isolation is formed on the surface of a silicon substrate 101 having p-type conductivity.
1 is formed and the silicon oxide film 102 is embedded by a CVD method such as a liquid phase CVD method.

Next, as shown in FIG. 3, the silicon substrate 1
The surface of 01 is oxidized to form a silicon oxide film 112.

At this time, a dilute hydrofluoric acid treatment of the silicon substrate 101 is performed as a pre-oxidation treatment. In order to effectively remove the contamination on the surface of the silicon substrate 101, other pretreatments such as hydrochloric acid treatment, hydrogen peroxide solution treatment, and ozone water treatment may be performed, but the final treatment is diluted hydrofluoric acid treatment. As a result, it is preferable to remove the oxide film on the surface of the silicon substrate 101.

Next, the silicon substrate 10 after the pretreatment is completed.
1 is conveyed into the casing 201 of the manufacturing apparatus shown in FIG. 1, and the silicon substrate 101 is heated to 900 ° C. by the heater 202. During this time, the inside of the housing 201 is, for example, 0.1 MPa.
Purge with N ₂ gas.

Next, after the temperature is raised, the inside of the housing 201 is exhausted through the exhaust port 20.
5 is exhausted, O ₂ gas is supplied from the gas supply pipe 203, and the internal pressure of the housing 201 is set to 666.6 Pa.

A microwave having an output of 200 W and a frequency of 2.45 GHz is applied to this O ₂ gas flow for 30 seconds from the discharge electrode 204, and the thickness is increased by radical oxidation using the downflow of oxygen plasma as shown in FIG. A silicon oxide film 112 having a thickness of 2 nm is formed.

Next, after the oxidation is completed, O _{2 is} discharged from the exhaust port 205.
The gas is exhausted and the output of the heater 202 is adjusted to control the temperature of the silicon substrate 101 to the silicon oxide film 112.
Set to the temperature used for surface nitriding.

Next, as shown in FIG. 4, the surface of the silicon oxide film 112 is nitrided by nitrogen atom radicals in a doublet state or a quartet state to form a silicon oxynitride film 103 as a gate insulating film. .

The nitriding of the surface of the silicon oxide film 112 was attempted in the following two ways. Hereinafter, nitridation using N ( ² D) in the doublet state, which is an excited state of a nitrogen atom radical, is the present invention (1), and nitridation using N ( ⁴ S) in the quartet state, which is the ground state, is the present invention. Call (2).

In the nitriding method according to the present invention (1), the output of the heater 202 is adjusted to adjust the substrate temperature to, for example, 300.degree.
And Three gas introduction pipes 206 ₁ , 206 ₂ , 206
N ₂ gas is introduced from ₃ and the internal pressure of the casing 201 is set to 1
It was set to 33.3 Pa. A wavelength of 248 nm (energy 5.00e) is emitted from a light irradiation port 208 directly below the ejection ports of the nozzle-shaped gas introduction pipes 206 ₁ , 206 ₂ , and 206 _3.
The excimer laser beam 209 of V) was irradiated.

With this excimer laser beam 209, N ₂
3 photon excitation (energy 15.00 eV) is performed to generate N ( ² D) that is a nitrogen atom radical in a doublet state,
Silicon substrate 101 on which silicon oxide film 112 is formed
Sprayed on the surface of. In this way, the silicon oxide film 1
The surface of 12 was nitrided. The processing time is, for example, the substrate temperature 3
It was 20 minutes at 00 ° C.

Next, the nitriding method according to the present invention (2) will be described.

First, the output of the heater 202 was adjusted so that the substrate temperature was set to 500 ° C., for example. Three gas introduction pipes 20
6 _{1, 206} 2, by introducing 206 ₃ from _{N 2} gas, the pressure was within the housing 201 for example, and 13.33 Pa. A microwave having an output of 100 W and a frequency of 2.45 GHz was applied to the gas flows N _{2 of the three} introduction pipes 206 ₁ , 206 ₂ , and 206 _{3 from} the three discharge electrodes 207 ₁ , 207 ₂ , and 207 ₃ , respectively, and nitrogen was supplied. Molecular plasma was set up. Light 209 having a wavelength of approximately 350 nm (energy 3.54 eV) was irradiated from a light irradiation port 208 directly below the ejection ports of the gas introduction pipes 206 ₁ , 206 ₂ , and 206 ₃ on the nozzle.

Nitrogen molecular plasma is generated by the irradiation light 209.
Nitrogen molecule radical N in_Two(A^ThreeΣ _u ⁺) And four
N (which is a nitrogen atom radical in the doublet state^FourGenerate S)
Then, the silicon substrate 1 on which the silicon oxide film 112 is formed
No. 01 surface was sprayed. In this way silicon oxidation
The surface of the film 112 was nitrided. The processing time is, for example, the substrate temperature.
The temperature was 500 ° C. and the time was 10 minutes.

As described above, after the nitriding of any one of the present inventions (1) and (2), the inside of the housing 201 is returned to the N ₂ purge atmosphere, the heater 202 is turned off, and the process is completed. It should be noted that the apparatus of FIG. 1 is added with a function capable of performing low pressure CVD of polysilicon performed in the next step,
A device capable of carrying the wafer to the device for carrying out D without exposing it to the atmosphere may be connected so that the gate electrode layer formation can be continuously performed without exposing it to the atmosphere.

Next, as shown in FIG. 5, a low pressure CVD method is used to deposit an arsenic-doped polysilicon film 104 at 650 ° C. on the entire surface of the substrate, and then a reactive ion etching method is used to form the polysilicon film. 104 and the silicon oxynitride film 103 are continuously etched to form a gate electrode portion having a predetermined shape.

Next, as shown in FIG. 6, an acceleration voltage of 40 k
eV, a dose of 2 × 10 ¹⁵ cm ^{- 2} low pressure conditions, by implanting arsenic ions into the substrate surface of the gate electrode portion as a mask to form a source region 105 and drain region 106 of high impurity concentration in a self-aligned manner . After this, low pressure CVD
Method is used to form a silicon oxide film 107 over the entire surface of the substrate.

Next, as shown in FIG. 7, the source region 10
5, a contact hole for connecting to the gate electrode 104 and the drain region 106 is formed with a silicon oxide film 107.
To open the hole. Finally, after forming an Al film on the entire surface of the substrate,
The Al film is patterned to form the source electrode 108, the gate electrode wiring 109, and the drain electrode 110, and n
Type MOS transistor is completed.

Although the manufacturing process of the n-type MOS transistor is shown in this embodiment, the basic manufacturing process is the same except that the conductivity types of the p-type MOS transistor are switched between n-type and p-type. .

FIG. 8 shows the SiON formed in this embodiment.
The distribution of nitrogen concentration in the film was measured by secondary ion mass spectrometry (SIM
This is the result of the examination in S). In the nitriding method of the present invention (1) using the nitrogen atom radical N ( ² D) in the doublet state, nitrogen is present at a high concentration almost only near the surface of the SiON film,
It can be seen that a steep distribution is realized.

Further, a nitrogen atom radical N (
^Although the nitriding method of the present invention (2) using ⁴ S) is inferior to that of the present invention (1), the concentration of nitrogen in the film is higher than that of the conventional example using nitrogen molecule radicals in nitrogen plasma.
It can be seen that the nitrogen concentration near the interface of the iO ₂ film / Si substrate is reduced.

FIG. 9 shows the SiON formed in this embodiment.
It is the result of having investigated the interface state of the film by the capacitance-voltage (CV) measurement.

Doublet state nitrogen atom radical N ( ² D)
In the nitriding method of the present invention (1) using, nitrogen is almost free from Si.
Reflecting the fact that it exists only in the vicinity of the surface of the ON film, the interface level is much less than one-tenth as compared with the conventional nitriding method using nitrogen molecule radicals, making it a good insulating film. You can see that

Further, the nitrogen atom radical N (
^In the nitriding method of the present invention (2) using ⁴ S), SiO ₂
Reflecting that the nitrogen concentration in the vicinity of the film / Si substrate interface is low, the interface level is reduced to one half or less as compared with the conventional one.

FIG. 10 shows the SiO formed in this embodiment.
And N film of the gate leakage current (J _g), is a diagram showing the relationship between the equivalent oxide thickness (EOT).

The nitriding method of the present invention (1) using nitrogen atom radicals in the doublet state, the nitriding method of the present invention (2) using nitrogen atom radicals in the quartet state, and the conventional method using nitrogen molecule radicals. The physical film thickness of both the SiON film formed by the nitriding method is about 2.0 nm.

Since the nitrogen concentration in the SiON film nitrided by the nitriding method of the present invention (1) is high, the dielectric constant of the SiON film is high, and a small EOT can be realized even with the same physical film thickness. I understand.

Even in the SiON film nitrided by the nitriding method of the present invention (2), since the nitrogen concentration in the film is higher than that of the SiON film nitrided by the conventional nitriding method, EO
T is also getting smaller. In all of these, the gate leak current is suppressed to a value sufficiently lower than that of the SiO ₂ film.

Next, referring to FIG. 11, when nitrogen atom radicals N ( ² D) in the doublet state and nitrogen atom radicals N ( ⁴ S) in the quartet state are used for nitriding the SiO ₂ film, nitrogen concentration enters the vicinity of the surface of the SiO ₂ film, SiO ₂ film /
The reason why the nitrogen concentration near the Si substrate interface is reduced will be described.

First, as shown in FIG. 11 (1) (a) of the present invention, considering the electron spin of the valence electron of the nitrogen atom radical, the nitrogen atom radical N ( ² D) in the doublet state.
A typical electron arrangement of valence electrons of N ( ² P) is ↑ ↓ ↑. Here, ↑ represents an electron having a spin quantum number of 1/2, and ↓ represents an electron having a spin quantum number of −1/2.

Since these radicals have an electron pair (↑ ↓), the spin of the valence electron enters the Si-O bond at ↑ ↓ and becomes Si-N.-O without cutting Si-O. That is, as shown in (b) of the present invention (1) in FIG. 11, N ( ² D) (N ( ² P)) + Si—O—Si → Si—N.—O—Si (1) Become.

As described above, the nitrogen atom radicals N ( ² D) and N ( ² P) in the doublet state are highly reactive, so that SiO
N highly penetrates into the Si-O bond on the outermost surface of the _two films.
Therefore, without cutting a part of the Si-O bond,
Since nitrogen atoms N are densely introduced into the network, after the SiON film having a high concentration of nitrogen atoms is formed near the surface, N ( ² D) or N ( ² P) in the doublet state or unreacted It suppresses the diffusion of other nitrogen source gas into the film. Therefore, by using the nitriding source gas containing the nitrogen atom radical in the doublet state, it becomes possible to form the SiON film in which the nitrogen atom N is introduced at a high concentration in the vicinity of the surface of the SiO ₂ film.

Further, as shown in (c) of the present invention (1) in FIG. 11, the EOT is small because the SiON film, which has been nitrided to a high concentration, is formed almost only in the vicinity of the surface of the SiO ₂ film.
Moreover, an ideal S in which the generation of interface states and fixed charges is suppressed with almost no nitrogen entering near the SiO ₂ / Si interface.
The iON film is realized by an ultrathin film having a film thickness of about 1.5 nm or less.

Next, as shown in (a) of the present invention (2) in FIG. 11, a typical electronic configuration of valence electrons of nitrogen atom radical N ( ⁴ S) in the quartet state is ↑↑↑. is there. Since this radical has no electron pair, it reacts with the Si-O bond (valence electron spin: ↑ ↓) to break the Si-O bond. That is, as shown in (b) of the present invention (2) in FIG. 11, N ( ⁴ S) + Si—O—Si → Si—N: + .O—Si (2).

Here, since the Si—O bond is partially broken, the nitrogen atom radical N ( ⁴
S) diffuses into the film from the part where this bond is broken. Therefore, the nitrogen atom radical N in the doublet state
SiO ₂ / S rather than using ( ² D) or N ( ² P)
Nitrogen atoms diffuse to the vicinity of the i interface.

However, since the nitrogen atom radical N ( ⁴ S) in the quartet state is more reactive than the conventional nitrogen molecule radical N ₂ ^* , the nitrogen atom radical N in the quartet state N
When ( ⁴ S) enters the SiO ₂ film, for example, 2N ( ⁴ S)
→ Deactivates due to the reaction of N ₂ . This reaction makes Si
Since the nitrogen concentration near the O ₂ surface increases and becomes dense, nitrogen atom radicals N ( ⁴ S) in the quartet state and other unreacted nitriding source gas in the atmosphere further diffuse near the SiO ₂ / Si interface. Is suppressed.

Due to these effects, nitriding in the vicinity of the SiO ₂ / Si interface is suppressed more than in the prior art, the generation of interface states and fixed charges is suppressed, and the dielectric constant of the SiON film is increased, resulting in a device having a small EOT. The SiON film can be applied to.

On the other hand, in the conventional N ₂ ^* nitriding, as shown in the conventional example (a) of FIG. 11, since the reactivity of N ₂ ^* is low, the nitrogen is not bonded and the nitrogen concentration in SiO ₂ does not increase.

Further, as shown in (b) of the conventional example of FIG. 11, when the nitrogen molecule radical N ₂ ^* is inserted into Si—O, the Si—O bond is broken and the SiO ₂ structure is greatly changed. Since it has low reactivity, it is neither bonded nor densified. Therefore, the nitrogen molecule radical N ₂ ^* in the atmosphere easily diffuses to the SiO ₂ / Si interface from the break of the Si—O bond. Due to these effects, the nitrogen concentration in the film becomes insufficient as shown in (c) of the conventional example of FIG.
Nitrogen was introduced into the interface of the O ₂ / Si substrate, and the interface state and fixed charge were generated.

In the SiON film formed by nitriding the silicon oxide film, it is said that it is more stable if the nitrogen atoms in the film are present in the form of (N-Si) ₃ . In order for the nitrogen atoms that have entered the film from the atmosphere to have this form, it is considered that oxygen atoms escape from the film or silicon atoms are supplied from the substrate.

In the present invention, since nitriding is performed by using nitrogen atom radicals, the concentration of nitrogen atoms supplied and retained in the film is increased, and SiO ₂ which was originally only Si--O.
There is also an effect that a (N-Si) ₃ shape can be easily formed therein.

FIG. 12 shows the ground state N ₂ (X ¹
It is a figure which shows the energy required in order to form various nitrogen atom radicals from (Sigma) _g ⁺ ).

Doublet state nitrogen atom radical N ( ² D)
In order to form the film, the nitrogen gas is irradiated with light for 12.14e.
It is understood that it is preferable to give energy of V or more. This energy may be given by multiphoton excitation. Further, in order to form the nitrogen atom radical N ( ² P) in the doublet state, the nitrogen gas or the nitriding source gas is irradiated with light to obtain 1
It can be seen that it is preferable to give energy of 3.34 eV or more.

When energy of 12.14 eV or more is applied to nitrogen gas, nitrogen atom radical N in the doublet state
( ² D) or N ( ² P) and the nitrogen atom radical N ( ⁴ S) in the quartet state are formed at a ratio of 1: 1, but in order to increase the production efficiency of the nitrogen atom radical in the doublet state, It is necessary to irradiate with light that gives energy such that the production efficiency of the nitrogen atom radical N ( ² D) or N ( ² P) in the doublet state is higher than the production efficiency of the nitrogen atom radical N ( ⁴ S) in the quartet state. There is.

Therefore, for example, in order to improve the production efficiency of the nitrogen atom radical N ( ² D) in the doublet state, it is preferable to irradiate the nitrogen gas with light to give energy of 14.53 eV or more.

Further, low temperature N_TwoWavelength 248n for crystal
m (energy 5.00 eV) excimer laser light
By irradiation, multiphoton excitation and interaction of multiple molecules
N ( ^TwoD) may be used for the generation. Nitrogen gas
In addition to NO and NH_ThreeA gas of molecules with equal nitrogen atoms
You may use.

Further, the nitrogen atom radical N (
^{In order} to form ⁴ S), it can be seen from FIG. 12 that nitrogen gas is preferably irradiated with light to give energy of 9.76 eV or more.

FIG. 13 shows the ground state N ₂ (X ¹
Sigma _{g ⁺⁾} and the excited state (molecular nitrogen radicals: a diagram showing the energy required for N 2 ^_*) to form various nitrogen atoms radicals from.

N ₂ ^* is an active species mainly present in the plasma of nitrogen gas. The method for producing a nitrogen atom radical using N ₂ ^* will be described below.

Doublet state nitrogen atom radical N ( ² D)
In order to generate, the nitrogen gas plasma may be irradiated with light to give energy of, for example, 5.92 eV or more to excite the nitrogen molecule radical N ₂ (A ³ Σ _u ⁺ ) in the plasma.

The doublet state nitrogen atom radical N (
To form a ^{2 P)} is a light in the plasma of the nitrogen gas may be given to e.g. 7.12eV or more energy irradiation.

Doublet state nitrogen atom radical N ( ² D)
In order to form selectively, the plasma of nitrogen gas may be irradiated with light to give energy of 8.31 eV or more.

In order to form the nitrogen atom radical N ( ⁴ S) in the quartet state, which is the ground state, plasma of nitrogen gas may be irradiated with light to give energy of 3.54 eV or more.

In these cases, in addition to nitrogen gas, NO and NH ₃
A gas of a molecule having an equal nitrogen atom can be used.

The above is the nitrogen molecule radical N ₂ (A
³ Σ _u ⁺ ) as an example, the case where a nitrogen atom radical in a doublet state or a nitrogen atom radical in a quartet state is generated from this has been described, but various nitrogen molecule radicals in various states shown in FIG. Excitation energy for nitrogen atom radicals may be used.

Further, in order to know the nitrogen atom radical concentration required in the nitriding source gas atmosphere, the abundance ratio of active species in this atmosphere was examined, and the nitrogen molecule radical N ₂ ^* was about 10%, and the quartet state was found. About 1% of nitrogen atom radicals N ( ⁴ S) and 0.1% of doublet state nitrogen atom radicals N ( ² D).
%, And the nitrogen atom radical N ( ² P) in the doublet state was about 0.01%.

At this time, in nitriding using nitrogen atom radicals, nitrogen atom radicals N in a quartet state in the atmosphere
( ⁴ S) is preferably 1% or more.

The doublet state nitrogen atom radical N (
^In nitriding using 2D) or N ( ² P), the nitrogen atom radical concentration in the doublet state in the atmosphere is preferably 0.1% or more.

Doublet state nitrogen atom radical N ( ² D)
In order to make the generation efficiency of N and N ( ² P) stand out, its content may be equal to or more than that of the nitrogen atom radical N ( ⁴ S) in the quartet state, that is, 0.5% or more.

The doublet state nitrogen atom radical N (
² D) and N ( ² P) are more reactive than the nitrogen atom radical N ( ⁴ S) in the quartet state, and the nitrogen atom radical N ( ⁴ S) in the quartet state is the nitrogen molecule radical N ₂ ^*. More reactive. Therefore, the nitrogen atom radical N in the doublet state
When nitriding the surface of the SiO ₂ film using ( ² D) or N ( ² P), more nitrogen atom radicals N ( ⁴ S) and nitrogen molecule radicals N ₂ ^{* in} the quartet state exist. Even in the atmosphere, it is possible to obtain the effect of nitriding by the nitrogen atom radicals N ( ² D) and N ( ² P) in the highly reactive doublet state.

Similarly, the nitrogen atom N ( ⁴
S) is used for nitriding the surface of the SiO ₂ film, the nitrogen atom radical N ( ⁴ ) in the quartet state with high reactivity is obtained even in an atmosphere in which more nitrogen molecule radicals N ₂ ^* are present.
The effect of nitriding with S) is obtained.

The pressure of the nitriding source gas is such that when N ( ⁴ S) in the quartet state, which is the ground state of the nitrogen atom radical, is used for nitriding, the nitrogen atom radical N in the quartet state is N.
In order to suppress the deactivation of ( ⁴ S) into nitrogen molecule N ₂ , it is preferable that the partial pressure of the gas molecule of the molecule having a nitrogen atom is 1333 Pa or less.

In addition, it is an excited state of a nitrogen atom radical.
Doublet state nitrogen atom radical N ( ^TwoD) or N (^Two
When P) is used for nitriding, nitrogen atoms in the doublet state
Zical N (^TwoD) or N (^TwoP) to quartet state
Elementary atom radical N (^FourS) or nitrogen molecule N_TwoDeactivation to
In order to suppress the
The pressure is preferably 133.3 Pa or less. Better
More preferably, the mean free path of gas molecules should be several cm or more.
The generated nitrogen atom radicals collide with other gas molecules.
Expected to collide with oxide film on silicon substrate surface before
The partial pressure is set to about 133.3 mPa or less.

In the excitation of nitrogen gas (gas of molecules having nitrogen atoms) by light irradiation, for example, laser light, lamp, synchrotron radiation light (SR) can be used as a light source. Not only one-photon excitation but also multiphoton excitation may be performed with these light sources.

The source gas for generating a nitrogen atom radical is a gas molecule having a nitrogen atom, such as N ₂ or NCl.
Any one of ₃ , NF ₃ , NH ₃ , NO, NO ₂ and N ₂ O or a mixed gas thereof is contained.

Although the heater 202 is resistance heating in FIG. 1, radiant heating by an infrared lamp may be used.

The light source of the excitation light is preferably provided with the light irradiation port 208 in a vacuum device in the vicinity of the nitriding atmosphere in order to prevent attenuation by nitrogen or oxygen in the atmosphere. In FIG. 1, the excitation light 2
Although 09 is introduced parallel to the surface of the substrate 101, the surface of the substrate 101 may be irradiated with excitation light.

As the plasma source, parallel plate plasma, inductively coupled plasma, helicon plasma, electron cyclotron resonance plasma or radical beam source may be used instead of microwave discharge. The discharge frequency is not limited to 2.45 GHz used in this embodiment, but is 13.
Other frequencies may be used, such as 56 MHz. The discharge output may be other than 200 W and 100 W used in this embodiment.

(Second Embodiment) Next, a second embodiment of the present invention.
A method of manufacturing the semiconductor device according to the present invention will be described. In this embodiment, a case will be described in which a laminated film of a high-k film / SiON film is formed as a gate insulating film of an n-type MOS transistor.

The present embodiment is different from the first embodiment in the step of forming the gate insulating film 103 on the silicon substrate 101, and therefore this part will be mainly described.

First, as in the first embodiment, as shown in FIG. 2, a deep groove 111 for element isolation is formed on the surface of a p-type silicon substrate 101, and CV such as liquid phase CVD is used.
The silicon oxide film 102 is embedded by the D method.

Next, as shown in FIG. 3, the silicon substrate 1
01 surface is oxidized to form a silicon oxide film 112.

As the oxidation pretreatment, the dilute hydrofluoric acid treatment of the silicon substrate 101 is performed as in the first embodiment.

The substrate 101 after the pretreatment is carried into the casing 201 of the manufacturing apparatus shown in FIG. 1 and radical-oxidized by the same method as in the first embodiment to obtain a silicon oxide film 112 having a thickness of 0.8 nm. To form. The processing conditions were, for example, a substrate temperature of 700 ° C., an atmospheric pressure of 5 Torr, and a processing time of 30 seconds.

Next, as shown in FIG. 14, the surface of the silicon oxide film 112 is nitrided by the present invention to form a silicon oxynitride film 113.

Two methods of nitriding the surface of the silicon oxide film 112 according to the present invention were tried as in the first embodiment.

As the nitriding method of the present invention (1), a nitrogen atom radical N ( ²
D) was generated and sprayed on the surface of the substrate 101 to nitride the surface of the silicon oxide film 112. The processing conditions were, for example, a substrate temperature of 300 ° C., an atmospheric pressure of 133.3 mPa, and a processing time of 10 minutes.

On the other hand, as the nitriding method of the present invention (2), nitrogen atom radicals N ( ⁴ S) in the quartet state are generated by the same method as in Embodiment 1 and sprayed onto the surface of the substrate 101 to form a silicon oxide film. The surface of 112 was nitrided. The processing conditions were, for example, a substrate temperature of 500 ° C., an atmospheric pressure of 13.33 Pa, and a processing time of 5 minutes.

After completion of any of the above nitriding, the casing 201
The inside is returned to the N ₂ purge atmosphere, the heater 202 is turned off, and the SiON film forming process is completed.

Next, as shown in FIG. 15, the SiON film 1
As a metal oxide layer, hafnium oxide (Hf
The O ₂ ) layer 114 is formed. In the present embodiment, these S
The laminated film of the iON film 113 and the HfO ₂ layer 114 is formed by hi
The gate insulating film 103 is used as the gh-k film.

Here, the substrate 101 on which the SiON film has been formed is taken out from the SiON film forming apparatus and placed in the metal oxide layer forming apparatus. A metal oxide film layer forming mechanism may be attached to the SiON film forming apparatus.
Care must be taken to prevent metal contamination of the membrane. Alternatively, an apparatus that can transfer the substrate from the SiON film forming apparatus to the metal oxide layer forming apparatus without exposing the substrate to the atmosphere may be connected. It is more preferable to continuously form the SiON film and the metal oxide layer by these measures.

In the metal oxide layer forming apparatus, for example, HfO ₂ having a film thickness of 2.5 nm is used at a substrate temperature of 300 ° C. by using a sputtering film forming method in an atmosphere having an oxygen partial pressure of 40 mTorr.
Is deposited on the SiON film and annealed in an oxygen atmosphere at 600 to 800 ° C.

The metal oxide layer 114 is formed by sputtering film forming method, laser ablation film forming method, vapor deposition method, CV.
Any of the D film forming methods may be used. Further, instead of the metal oxide layer 114, a solid solution (silicate) layer of metal oxide and silicon oxide may be formed.

As the metal oxide layer, for example, Ta ₂ O ₅ ,
TiO ₂ , ZrO ₂ , HfO ₂ , La ₂ O ₃ , Gd ₂ O
₃ , Sc ₂ O ₃ , Pr ₂ O ₃ , Nd ₂ O ₃ , Sm
₂ O ₃ , Eu ₂ O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ , Yb ₂
It is preferable to contain at least one of O ₃ and Y _x O _y .

As a solid solution (silicate) layer of metal oxide and silicon oxide, Zr _x Si _y O _z and Hf _{x are used.}
Si _y O _z , La _x Si _y O _z , T _x Si _y O _z , La
_x Al _y O _z , Zr _x Ti _y O _z , Sn _x Ti _y O _z ,
Those containing at least one of Sr _x Zr _y O _z and Ba _x Zr _y O _z are preferable.

Further, the metal oxide layer forming apparatus is provided with a function capable of performing low pressure CVD of polysilicon in the next step, or an apparatus capable of transporting a wafer to an apparatus for performing low pressure CVD of polysilicon without exposing to the atmosphere. May be connected so that the gate electrode layer formation, which is the next step, can be continuously performed.

Next, as in the first embodiment, a gate electrode portion is formed as shown in FIG.

Next, as shown in FIG. 6, the source diffusion layer 1
05 and the drain diffusion layer 106 are formed.

Next, as shown in FIG. 7, Al wiring is sequentially formed to form a source electrode 108, a drain electrode 110 and a gate electrode 109, thereby completing an n-type MOS transistor.

FIG. 16 shows the HfO formed in this embodiment.
The gate leakage current (J _g ) of the ₂ / SiON laminated film,
It is a figure which shows the relationship with an oxide film conversion film thickness (EOT).

By using the SiON film formed by the nitriding method of the present invention (1), by using the SiON film formed by the nitriding method of the present invention (2), by the conventional nitriding method using nitrogen molecular plasma. Formed SiON
The base oxide film 112 before nitriding has a film thickness of 0.8 nm and the HOTO ₂ layer has an EOT of about 0.5.
nm.

Doublet Nitride Atomic Plasma N ( ² D)
In the case of nitriding according to the present invention (1) in which E., the EOT of the entire laminated film is about 1.0 nm, and the EOT of the SiON film is
The OT is suppressed to about 0.5 nm.

In addition, the quartet state nitride atomic plasma N (
^{In the case} of nitriding according to the present invention (2) using ⁴ S), the EOT of the entire laminated film is larger than that according to the present invention (1), but smaller than that of the conventional example using nitrogen molecular plasma. You can see that

In all of these, the gate leak current is suppressed to a value sufficiently lower than that of SiO ₂ . On the other hand, when the conventional nitriding method is used, the EO of the entire laminated film is
T is about 1.6 nm, and the EOT of the SiON film is about 1.
It has increased to 1 nm.

On the other hand, the nitriding method according to the present invention (2), more preferably the nitriding method according to the present invention (1), suppresses an increase in the film thickness of the SiON film due to the oxidizing atmosphere during the formation of the metal oxide layer. You can see that

Next, referring to FIG. 17, when nitrogen atom radicals N ( ² D) in the doublet state and nitrogen atom radicals N ( ⁴ S) in the quartet state are used for nitriding the SiO ₂ film, The reason why the EOT after forming the oxide layer / SiON laminated film becomes small will be described.

When forming the metal oxide layer, methods such as sputtering, vapor deposition, laser ablation, CVD and annealing in an atmosphere containing O ₂ are used.
The SiON film is exposed to an oxidizing atmosphere.

In the nitriding method of the present invention (1), since the surface of the SiO ₂ film is nitrided by using the nitrogen atom radical N ( ² D) in the doublet state, the nitrogen concentration near the surface of the SiON film is extremely high. . The high concentration of nitrogen near this surface
As shown in (a) of the present invention (1) in FIG. 17, since O _{2 in the} atmosphere for forming the metal oxide layer (MO _x ) is suppressed from diffusing into the SiON film, the film thickness of the SiON film due to oxidation is suppressed. The increase is suppressed, and the EOT of the SiON film which is smaller than the base oxide film due to nitriding is also suppressed. Moreover, since the nitrogen atoms are localized at a high density on the surface of the SiON film, the surface becomes dense and oxygen atoms and nitrogen atoms do not diffuse into the metal oxide layer and the SiO ₂ film.

Therefore, as shown in (b) of the present invention (1) in FIG. 17, the physical film thickness of the entire high-k gate insulating film after MO _x formation becomes small and the EOT also becomes small.

In the nitriding method according to the present invention (2), the surface of the SiO ₂ film is nitrided by using the nitriding radical N ( ⁴ S) in the quartet state.
The nitrogen concentration near the surface of the ON film is high. As shown in (a) of the present invention (2) in FIG. 17, the nitrogen in the vicinity of the surface suppresses O ₂ in the MO _x forming atmosphere from diffusing into the SiON film to some extent. Of the SiON film is suppressed compared with the conventional example, and the increase of EOT of the SiON film is also suppressed.

Therefore, as shown in (b) of the present invention (2) of FIG. 17, the physical film thickness of the entire high-k gate insulating film after MO _x formation becomes small, and EOT also becomes small.

On the other hand, if the surface of the SiO ₂ film is nitrided using the conventional nitrogen molecule radicals, not only the nitrogen concentration near the surface is low, but also the nitrogen atoms diffuse to the silicon substrate interface. Therefore, O _{2 in the} MO _x forming atmosphere is S
Since it diffuses into the iON film and its film thickness increases, the EOT of the SiON film also increases.

Therefore, as shown in (b) of the conventional example of FIG. 17, the physical film thickness of the entire high-k gate insulating film after MO _x formation becomes large.

Here, containing silicon atoms and oxygen atoms
The insulating film layer to be formed is formed by, for example, oxidizing the surface of Si.
SiO_TwoTo use. For the oxidation, a gas component having an O atom is used.
Use an atmosphere that includes children. For example, dry acid
Conversion, wet oxidation, O _TwoPlasma and O_TwoOf gas
Radical oxidation and ozone oxidation by light irradiation are used.

A solid solution (silicate) layer of metal oxide and silicon oxide may be used as the insulating film layer nitrided in the present invention. In addition, chemical vapor deposition (CV
A SiO ₂ film deposited by the method D) may be used. Also, N
It may be a silicon oxynitride film formed by oxynitriding the silicon surface or the silicon oxide film surface with O, N ₂ O, NO ₂ , or the like. In this case, it is preferable that the nitrogen concentration in the vicinity of the SiON / Si interface is so low that the interface state and fixed charges do not matter.

[0148]

According to the present invention, a SiON film having a sufficiently high nitrogen concentration can be formed, a SiON film in which nitrogen atoms are localized in the vicinity of the surface thereof can be formed, and even if a metal oxide is formed, E
The OT film thickness does not increase and oxygen atoms and nitrogen atoms do not diffuse into each other.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a silicon oxynitride film manufacturing apparatus according to the present invention.

FIG. 2 is a sectional view showing a manufacturing process of the n-type MOS transistor according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a manufacturing process of the n-type MOS transistor according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a manufacturing process of the n-type MOS transistor according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing a manufacturing process of the n-type MOS transistor according to the first embodiment of the present invention.

FIG. 6 is a sectional view showing a manufacturing process of the n-type MOS transistor according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view showing the manufacturing process of the n-type MOS transistor according to the first embodiment of the present invention.

FIG. 8 is a diagram showing nitrogen atom distributions of a silicon oxynitride film formed in Embodiment 1 of the present invention and a silicon oxynitride film formed by a conventional nitriding method.

FIG. 9 is a diagram showing interface state densities of a silicon oxynitride film formed in Embodiment 1 of the present invention and a silicon oxynitride film formed by a conventional nitriding method.

FIG. 10 shows the relationship between the gate leakage current and the EOT (oxide equivalent film thickness) of the silicon oxynitride film formed in Embodiment 1 of the present invention and the silicon oxynitride film formed by the conventional nitriding method. Fig.

FIG. 11 is a diagram for explaining the reason why the nitrogen concentration distribution in the silicon oxynitride film differs depending on the nitriding species.

FIG. 12 is a diagram showing energies required to form various nitrogen atom radicals from the ground state of nitrogen molecule N ₂ .

FIG. 13 is a diagram showing energies required to form various nitrogen atom radicals from a ground state and an excited state (nitrogen molecule radical) of nitrogen molecule N ₂ .

FIG. 14 is a cross-sectional view showing the manufacturing process of the n-type MOS transistor according to the second embodiment of the present invention.

FIG. 15 is a sectional view showing a manufacturing process of the n-type MOS transistor according to the second embodiment of the present invention.

FIG. 16 is an EO of a metal oxide layer / silicon oxynitride film laminated film formed in Embodiment 2 of the present invention and a metal oxide layer / silicon oxynitride film laminated film formed by a conventional nitriding method.
The figure which shows the relationship between T (oxide film conversion film thickness) and gate leak current.

FIG. 17 is a diagram for explaining the reason why the EOT (oxide film equivalent film thickness) of the metal oxide layer / silicon oxynitride film laminated film is different due to the difference in nitriding species.

[Explanation of symbols]

101 ... p-type silicon substrate 102 ... Silicon oxide film 103 ... Gate insulating film 104 ... Gate electrode 105 ... Source area 106 ... Drain region 107 ... Silicon oxide film 108 ... Source electrode 109 ... Gate electrode wiring 110 ... Drain electrode 111 ... Silicon oxide film embedded trench 112 ... Silicon oxide film 113 ... Silicon oxynitride film 114 ... Metal oxide layer 201 ... Oxynitriding device housing 202 ... Heater 203, 206 ... Gas supply pipe 204, 207 ... Discharge electrodes 205 ... Exhaust port 208 ... Light irradiation port 209 ... Excitation light 210 ... Nitrogen atom radical flow

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideki Satake             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center F term (reference) 5F058 BA20 BC11 BF73 BF74 BJ04                 5F140 AA00 BA01 BD01 BD05 BD09                       BD11 BD12 BD13 BD15 BE02                       BE07 BE08 BE09 BE10 BF01                       BF04 BF11 BF15 BG28 BG38                       BJ01 BJ05 BK13 CB04 CC03                       CC12 CE10

Claims (12)

[Claims] 1. A method of supplying a nitriding source gas containing nitrogen atom radicals in a doublet state or a quartet state to the surface of an insulating film containing silicon atoms and oxygen atoms to nitride the surface of the insulating film. A method for manufacturing an oxynitride film, comprising: 2. A nitriding source gas containing a nitrogen atom radical in a doublet state or a quartet state is supplied to the surface of an insulating film layer containing a silicon atom and an oxygen atom formed on a silicon layer, And a step of nitriding a surface of the insulating film, and a step of forming a metal oxide film or a solid solution film of a metal oxide and silicon oxide on the nitrided surface of the insulating film. Manufacturing method of semiconductor device. 3. A nitriding source gas containing nitrogen atom radicals in the doublet state is generated by irradiating a gas of a molecule having a nitrogen atom with light to give energy of 12.14 eV or more. The method for producing an oxynitride film according to claim 1. 4. A nitriding source gas containing nitrogen atom radicals in the doublet state is produced by irradiating plasma of a gas of a molecule having nitrogen atoms with light to give energy of 5.92 eV or more. The method for producing an oxynitride film according to claim 1, wherein 5. A nitriding source gas containing nitrogen atom radicals in the doublet state is generated by irradiating a gas of a molecule having a nitrogen atom with light to give energy of 14.53 eV or more. The method for producing an oxynitride film according to claim 1. 6. A method for producing a nitriding source gas containing nitrogen atom radicals in the doublet state by irradiating plasma of a gas of a molecule having nitrogen atoms with light to give energy of 8.31 eV or more. The method for producing an oxynitride film according to claim 1, wherein 7. The oxynitride film according to any one of claims 3 to 6, wherein the nitriding source gas has a partial pressure of a gas of a molecule having nitrogen atoms is 133.3 Pa or less. Production method. 8. A nitriding source gas containing nitrogen atom radicals in the quartet state is generated by irradiating a gas of a molecule having a nitrogen atom with light to give energy of 9.76 eV or more. The method for producing an oxynitride film according to claim 1. 9. A nitriding source gas containing nitrogen atom radicals in the quartet state is produced by irradiating plasma of a gas of molecules having nitrogen atoms with light to give energy of 3.54 eV or more. The method for producing an oxynitride film according to claim 1, wherein 10. The method for producing an oxynitride film according to claim 8, wherein the nitriding source gas has a partial pressure of a gas of a molecule having a nitrogen atom of 1333 Pa or less. 11. The gas of a molecule having a nitrogen atom is N ₂ , NCl ₃ , NF ₃ , NH ₃ , NO, NO ₂ , N _2.
The method for producing an oxynitride film according to claim 3, wherein the oxynitride film contains any one of O. 12. The metal oxide film is made of Ta ₂ O ₆ or TiO _2.
2 , ZrO ₂ , HfO ₂ , La ₂ O ₃ , Gd ₂ O ₃ , S
_{c 2 O 3, Pr 2 O} 3, Nd 2 O 3, Sm 2 O 3, Eu
₂ O ₃ , Dy ₂ O ₃ , Ho ₂ O ₃ , Yb ₂ O ₃ , Y _x O
The solid solution film containing any one of _{y and} the metal oxide and the silicon oxide is Zr _x Si _y O _z or Hr _x Si.
_{y O z, La x Si y} O z, Ti x Si y O z, La x
Al _y O _z , Zr _x Ti _y O _z , Sn _x Ti _y O _z , S
3. The method for manufacturing a semiconductor device according to claim 2, further comprising one of r _x Zr _y O _z and Ba _x Zr _y O _z .