JPH04249366A - Thin film laminated device with substrate - Google Patents

Abstract

PURPOSE:To eliminate shift in pattern formation due to elastic anisotropy of a plastic in the case where the plastic is used as a substrate of a thin film laminated layer device. CONSTITUTION:Conventionally, a crystalline plastic which is extended and processed as a plastic substrate is used. However, since this is a cause for generating a shift in pattern formation, an amorphous plastic is adopted as a substrate.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD The present invention relates to a thin film laminated device, and more particularly to a switching element that can be suitably used in flat panel displays for office automation equipment, TVs, and the like.

0002

2. Description of the Related Art There is a strong demand for the use of large-area liquid crystal panels in office automation equipment terminals and liquid crystal TVs, and for this reason, in the active matrix system, a switch is provided for each pixel to maintain the voltage. Further, in recent years, there have been active efforts to reduce the weight and cost of liquid crystal panels, and the use of plastic for the substrates of switching elements is being considered. However, when a thin film laminated switching element is formed on plastic, there are problems such as deformation and curling of the plastic substrate, and film peeling. Additionally, when manufacturing thin film laminated switching elements, there is a photolithography process in which plastic is immersed in a solution of acid, alkali, water, etc., and acid, alkali, water, etc. remain in the plastic, which can cause element deterioration. became. When finely patterning a thin film stacked device, expansion and contraction of the substrate causes pattern shift, making it difficult to expose a large area at once. Furthermore, the anisotropy of substrate expansion and contraction made pattern formation even more difficult. In manufacturing a liquid crystal display device using a plastic film substrate, it is necessary to use an alignment method unique to plastics during alignment treatment. However, SiO
Japanese Patent Publication No. 1-47769 discloses that by forming two layers on one side of a plastic film, alignment treatment can be performed in the same manner as for glass substrates.

0003

[Object] The object of the present invention is to solve the above-mentioned conventional problems and provide a thin film laminated device that is lightweight, low cost, free of film peeling, curling, etc., and has good reliability.

0004

[Structure] In order to achieve the above object, the present inventors
As a result of repeated research and consideration of fabricating switching elements on lightweight, inexpensive plastic, it became clear that curling is the biggest problem when using plastic film due to the deformation of the plastic substrate during the element fabrication process. . It was discovered that the causes of plastic deformation and plastic film curling are the internal stress of laminated thin films, thermal expansion and contraction of plastic, and swelling due to acids, alkalis, and water, and developed plastics with thin films made of inorganic substances formed on both sides. It has become clear that using a substrate is effective. Furthermore, when thin film laminated devices are microfabricated on the above-mentioned substrates, the stretching anisotropy of the plastic substrates has become a problem. They discovered that the cause of this was the structural anisotropy of the plastic substrate, and found that it was effective to use an amorphous plastic substrate with a thin film made of an inorganic substance formed on both sides, and completed the present invention. reached. That is, the present invention provides a thin film laminated device with a substrate and a thin film laminated device formed on the substrate, wherein the substrate is an amorphous plastic with thin films made of an inorganic substance formed on both surfaces thereof. Regarding. Further, the transmittance of the amorphous plastic substrate of the thin film laminated device is preferably 80% or more at a wavelength of 400 to 850 nm. Formation of inorganic thin films on plastic substrates is important for solving problems such as peeling of thin film laminated devices fabricated thereon. If the thin film is formed only on one side of the plastic substrate (film), curling will occur depending on the internal stress of the inorganic thin film, resulting in problems such as handling. In order to avoid this, it is important to form inorganic thin films on both sides of the plastic substrate (film). When the thin film laminated device of the present invention is used in a liquid crystal display driving element, in order to ensure display contrast, it is preferable that the plastic substrate has a transmittance of 80% or more in the wavelength range of 400 to 850 nm. In order to produce the thin film laminated device of the present invention, first, polyarylate,
SiOx (1≦x≦2), Si:O: on both sides of amorphous plastic or plastic film such as polyethersulfone, polyetherimide, polysulfone, etc.
N, Si:O:H, Si:N:H, Si:O:N:H,
Si3N4, TiO2, ZnS, ZnO, Al2O3,
AlN, MgO, GeO, ZrO2, Nb2O5, Si
Inorganic substances such as C and Ta2O5 are deposited by sputtering, vapor deposition,
It is formed to a thickness of 300 to 10,000 Å by a plasma CVD method or the like. The inorganic substance may be crystalline or amorphous, but amorphous is preferable because it has no stretching anisotropy and does not allow moisture to enter through grain boundaries. In order to make these inorganic substances amorphous, the substrate temperature is set to 200°C or lower, preferably 150°C or lower, and sputtering or plasma CV
It is preferable to produce by method D. The formed thin film does not necessarily need to have the same inorganic substance on both sides, nor does it need to have the same film thickness. Particularly preferred inorganic substances include SiO2, Si3N4, Si:N:O, Si:O:
Examples include H, Si:N:H, Si:O:N:H, and AlN. The thickness of the plastic used is 50 μm to 2 mm, but preferably 500 μm or less, particularly 300 μm or less. The glass transition point of the plastic is preferably 150°C or higher, particularly preferably 180°C or higher. Furthermore, a thin film laminated device is formed on the plastic coated on both sides with an inorganic material. As a thin film laminated device, an MIM type element with a metal-insulator-metal layer structure, JP-A-61-275
MSI element (Metal-
Semi-Insulator), SIS element with semiconductor-insulator-semiconductor layer structure, MIMI of metal-insulator-metal-insulator-metal described in JP-A-64-7577
There are M elements, etc. Among these, an MIM type element using a hard carbon film as an insulator is advantageous. When a hard carbon film is used as an insulating layer, the plastic substrate (film) will curl significantly, so this can be countered by forming an inorganic film on both sides of the substrate to increase the rigidity of the substrate.

Next, a method for manufacturing the above-mentioned element will be explained in detail with reference to FIGS. 1 to 3. First, a transparent electrode material for a pixel electrode is deposited by a method such as vapor deposition or sputtering on a plastic substrate 1 whose both sides are coated with the above-mentioned inorganic substance (2a, 2b), and patterned into a predetermined pattern.
Next, a conductor thin film for the lower electrode is formed by a method such as vapor deposition or sputtering, and a predetermined pattern is formed by wet or dry etching to form the first conductor 7 that will become the lower electrode. After coating the hard carbon film 2 using methods such as dry etching, wet etching, or a lift-off method using a resist, it is patterned into a predetermined pattern to form an insulating film, and then a conductive thin film for a bus line is formed on the insulating film by a method such as vapor deposition or sputtering. is coated and patterned into a predetermined pattern to form a second conductor 6 that will become a bus line.Finally, an unnecessary portion of the lower electrode is removed to expose a transparent electrode pattern to form a pixel electrode 4. In this case, the configuration of the MIM element is not limited to this, but after the MIM element is fabricated, a transparent electrode is provided on the top layer, a transparent electrode also serves as an upper or lower electrode, a side surface of the lower electrode, etc. Various modifications are possible, such as one in which an MIM element is formed on the top. Here, the thickness of the lower electrode, the upper electrode, and the transparent electrode is usually in the range of several hundred to several thousand Å, several hundred to several thousand Å, and several hundred to several thousand Å, respectively. The thickness of the hard carbon film is 100 to 8000 Å, preferably 200 Å.
~6000 Å, more preferably 300 to 4000 Å. Furthermore, in the case of plastic substrates, it has been extremely difficult to fabricate active matrix devices using active elements due to their heat resistance. However, a hard carbon film can be produced at a substrate temperature of about room temperature, and can also be produced on a plastic substrate, making it a very effective means for improving image quality.

Next, the material of the MIM element used in the present invention will be explained in more detail. The material of the first conductor 1 serving as the lower electrode includes Al, Ta, Cr, W, Mo, and Pt.
, Ni, Ti, Cu, Au, W, ITO, ZnO:Al
, In2O3, SnO2, etc. are used.

Next, the materials for the second conductor 3 that will become the bus line include Al, Cr, Ni, Mo, Pt, Ag, Ti,
Cu, Au, W, Ta, ITO, ZnO:Al, In2
Various conductors such as O3 and SnO2 are used, but I-V
Ni, because of its particularly excellent stability and reliability of properties,
Pt and Ag are preferred. In the MIM element using the hard carbon film 2 as an insulating film, the symmetry does not change even if the type of electrode is changed, and it can be seen from the relationship lnI∝√v that Poole-Frenkel type conduction is performed. Also, from this fact, this kind of M
It can be seen that in the case of an IM element, the upper electrode and lower electrode may be combined in any manner. However, the device characteristics (IV characteristics) deteriorate and change depending on the adhesion between the hard carbon film and the electrode and the state of the interface. Considering these, Ni, P
It was found that t,Ag is good. The current-voltage characteristics of the MIM element of the present invention are shown in FIG. 2, and approximately expressed by the conduction equation shown below.

[0008]

[Math 1]

I: Current V: Applied voltage κ: Conductivity coefficient β: Poole-Frenkel coefficient n: Carrier density μ: Carrier mobility q:
Electron charge Φ: Trap depth ρ: Specific resistance d: Film thickness of hard carbon (Å) k: Boltzmann constant T: Ambient temperature ε1: Dielectric constant of hard carbon ε2: Vacuum dielectric constant

The hard carbon film in the present invention will be explained in detail. An organic compound gas, especially a hydrocarbon gas, is used to form a hard carbon film. The phase state of these raw materials does not necessarily have to be a gas phase at normal temperature and pressure; they can be used in either a liquid or solid phase as long as they can be vaporized through melting, evaporation, sublimation, etc. by heating or reduced pressure. be. Regarding the hydrocarbon gas as the raw material gas, for example, paraffinic hydrocarbons such as CH4, C2H6, C3H8, C4H10, acetylenic hydrocarbons such as C2H4,
Gases containing at least all hydrocarbons such as olefinic hydrocarbons, diolefinic hydrocarbons, and even aromatic hydrocarbons can be used. Furthermore, other than hydrocarbons, compounds containing at least the carbon element can be used, such as alcohols, ketones, ethers, esters, CO, and CO2. In the method of forming a hard carbon film from a raw material gas in the present invention, the film-forming active species is
It is preferable to use a plasma state generated by a plasma method using direct current, low frequency, high frequency, microwave, etc., but for the purpose of increasing the area, improving uniformity, and forming a film at a low temperature, A method using a magnetic field effect is more preferable. Active species can also be formed by thermal decomposition at high temperatures. In addition, it may be formed through an ion state generated by an ionization vapor deposition method, an ion beam vapor deposition method, etc., or a vacuum vapor deposition method,
Alternatively, it may be formed from neutral particles produced by a sputtering method or the like, or may be formed from a combination of these. An example of the deposition conditions for the hard carbon film produced in this manner is as follows in the case of the plasma CVD method. RF output: 0.1 to 50 W/cm2 Pressure: 1/103 to 10 Torr Deposition temperature: Room temperature to 350°C Due to this plasma state, the raw material gas is decomposed into radicals and ions and reacts, thereby forming carbon atoms C on the substrate.
A hard carbon film containing at least one of amorphous (amorphous) and microcrystalline (crystal size is several tens of angstroms to several μm) is deposited. Further, Table 1 shows various properties of the hard carbon film.

[0011]

[Table 1]

Note) Measurement method; Specific resistance (ρ): I-V using a coplanar cell
Determined from characteristics. Optical bandgap (Egopt): Obtain the absorption coefficient (α) from the spectral characteristics and determine from the relationship shown in Equation 2.

[Equation 2] Amount of hydrogen in the film [C(H)]: 29 from the infrared absorption spectrum
It is determined by integrating the peak near 00/cm and multiplying it by the absorption cross section A. That is, [C(H)]=A・∫α(v)/V
・dv SP3/SP2 ratio: The infrared absorption spectrum is
It is decomposed into Gaussian functions respectively attributed to P2, and determined from the area ratio thereof. Vickers hardness (H): Based on micro Vickers meter. Refractive index (n): By ellipsometer. Defect density: Based on ESR.

The hard carbon film thus formed was analyzed by Raman spectroscopy and IR absorption, and the results are shown in FIGS. 5 and 6, respectively.
and 7, the carbon atom has a hybrid orbital of SP3 and SP
It has become clear that there are interatomic bonds that form a hybrid orbital of 2. The ratio of SP3 bonds to SP2 bonds can be approximately estimated by peak-separating the IR spectrum. IR spectrum includes 2800-3150/c
Although the spectra of many modes overlap in the measurement, the attribution of the peak corresponding to each wave number is clear, and the peak area is calculated by separating the peaks using a Gaussian distribution as shown in Figure 5. , if you find the ratio, S
You can know P3/SP2. Moreover, according to X-ray and electron diffraction analysis, it has been found that it is in an amorphous state (a-C:H) and/or an amorphous state containing microcrystalline grains of about 50 Å to several μm. In the case of the plasma CVD method, which is generally suitable for mass production, the lower the RF output, the higher the specific resistance and hardness of the film, and the lower the pressure, the longer the life of active species, so lowering the substrate temperature and increasing the The area can be made uniform, and the specific resistance and hardness tend to increase. Furthermore, since the plasma density decreases at low pressures,
A method using the magnetic field confinement effect is particularly effective in increasing resistivity. Furthermore, this method has the characteristic that it can form a hard carbon film of good quality even under relatively low temperature conditions of about room temperature to 150° C., so it is optimal for lowering the temperature of the MIM element manufacturing process. Therefore, the degree of freedom in selecting the substrate material to be used is increased, and the substrate temperature can be easily controlled, so that a uniform film can be obtained over a large area. Furthermore, as shown in Table 1, the structure and physical properties of the hard carbon film can be controlled over a wide range, so there is an advantage that device characteristics can be designed freely. Furthermore, the dielectric constant of the film is 2 to 6, which is Ta2, which is used in conventional MIM devices.
Since it is smaller than O5, Al2O3, and SiNx, when making an element with the same capacitance, the element size only needs to be larger, so microfabrication is not required and the yield is improved (due to the driving conditions, LCD The capacitance ratio of C(LCD)/C(MIM) = approximately 10:1 is required between C(LCD) and MIM element. Also, since the element steepness β∝1/√ε・√d, the smaller the dielectric constant ε, the greater the steepness.
The ratio between the on-current Ion and the off-current Ioff can be increased. Therefore, LCD with lower duty ratio
This makes it possible to drive a high-density LCD. Furthermore, since the film has high hardness, there is less damage caused by the rubbing process during encapsulation of the liquid crystal material, which also improves the yield. Considering the above points, by using a hard carbon film, a low-cost, gradation (color), and high-density LCD can be realized.

Furthermore, this hard carbon film contains, in addition to carbon atoms and hydrogen atoms, Group III elements, Group IV elements, Group V elements of the periodic table, alkali metal elements, alkaline earth metal elements, and nitrogen atoms. , an oxygen element, a chalcogen-based element, or a halogen atom may be included as a constituent element. 1 of the constituent elements
Group III elements of the periodic table, as well as group V elements,
Those into which alkali metal elements, alkaline earth metal elements, nitrogen atoms, or oxygen atoms are introduced can make the hard carbon film about 2 to 3 times thicker than non-doped ones.
Moreover, this can prevent the occurrence of pinholes during device fabrication and dramatically improve the mechanical strength of the device. Further, in the case of a nitrogen atom or an oxygen atom, the same effect as in the case of a group IV element of the periodic table as described below can be obtained. Similarly, devices incorporating Group IV elements of the periodic table, chalcogen elements, or halogen elements dramatically improve the stability of the hard carbon film and improve the hardness of the film, resulting in highly reliable elements. can be made. These effects can be obtained because Group IV elements and chalcogen elements reduce the active double bonds present in the hard carbon film, and in the case of halogen elements, 1) abstraction for hydrogen The reaction promotes the decomposition of the raw material gas and reduces dangling bonds in the film, and 2) during the film formation process, the halogen element X pulls out hydrogen in the C-H bond and replaces it, forming a C-X bond. enters the film, and the bond energy increases (the bond energy between C-H and C-X is
This is because the distance between X is larger. In order to use these elements as constituent elements of the film, in addition to hydrocarbon gas and hydrogen as raw material gases, it is necessary to add elements from periodic table I as dopants to the film.
In order to contain a group II element, a group IV element, a group V element, an alkali metal element, an alkaline earth metal element, a nitrogen atom, an oxygen atom, a chalcogen element, or a halogen element, these elements or atoms are added. Compounds (or molecules) containing (
Hereinafter, these gases may also be referred to as "other compounds").

Examples of compounds containing Group III elements of the periodic table include B(OC2H5)3, B2H6, B2H6,
Cl3, BBr3, BF3, Al(O-i-C3H7)
3, (CH3)3Al, (C2H5)3Al, (i-C
4H9)3Al,AlCl3,Ga(O-i-C3H7
)3, (CH3)3Ga, (C2H5)3Ga, GaC
l3, GaBr3, (O-i-C3H7)3In, (C
2H5)3In etc. Examples of compounds containing Group IV elements of the periodic table include Si2H6, (C2H5)3S
iH, SiF4, SiH3Cl, SiCl4, Si(O
CH3)4,Si(OC2H5)4,Si(OC3H7
)4, GeCl4, GeH4, Ge(OC2H5)4,
Ge(C2H5)4, (CH3)4Sn, (C2H5)
4Sn, SnCl4, etc. Examples of compounds containing Group V elements of the periodic table include PH3, PF3, PF5, P
Cl2F3, PCl3, PCl2F, PBr3, PO(
OCH3)3, P(C2H5)3, POCl3, AsH
3, AsCl3, AsBr3, AsF3, AsF5, A
sCl3, SbH3, SbF3, SbCl3, Sb(O
C2H5)3 etc. Examples of compounds containing alkali metal atoms include LiO-i-C3H7, NaO-i-
There are C3H7, KO-i-C3H7, etc. Examples of compounds containing alkaline earth metal atoms include Ca(OC2H
5) 3, Mg(OC2H5)2, (C2H5)2Mg, etc. Examples of compounds containing nitrogen atoms include nitrogen gas, inorganic compounds such as ammonia, organic compounds having functional groups such as amino groups and cyano groups, and nitrogen-containing heterocycles. Examples of compounds containing oxygen atoms include oxygen gas, ozone, water (steam), hydrogen peroxide, carbon monoxide, carbon dioxide, suboxide, nitrogen monoxide, nitrogen dioxide, dinitrogen trioxide, and dinitrogen pentoxide. , inorganic compounds such as nitrogen trioxide,
Organic compounds having functional groups or bonds such as hydroxyl groups, aldehyde groups, acyl groups, ketone groups, nitro groups, nitroso groups, sulfone groups, ether bonds, ester bonds, peptide bonds, heterocycles containing oxygen, metal alkoxides, etc. can be mentioned. Compounds containing chalcogen elements include:
For example, H2S, (CH3) (CH2)4S(CH2)4
CH3,CH2=CHCH2SCH2CH=CH2,C
2H5SC2H5, C2H5SCH3, thiophene, H
There are 2Se, (C2H5)2Se, and H2Te. Compounds containing halogen elements include, for example, fluorine, chlorine,
Bromine, iodine, hydrogen fluoride, carbon fluoride, chlorine fluoride, bromine fluoride, iodine fluoride, hydrogen chloride, bromine chloride, iodine chloride, hydrogen bromide, iodine bromide, hydrogen iodide, and other inorganic compounds, halogens Organic compounds such as alkyl oxides, aryl halides, styrene halides, polymethylene halides, and haloforms are used.

[0016] A hard carbon film suitable as a liquid crystal driving MIM element has a film thickness of 100 to 8000 Å and a specific resistance of 10 6 to 10 13 Ω·cm, depending on the driving conditions. In addition, considering the margin between drive voltage and withstand voltage (dielectric breakdown voltage), it is desirable that the film thickness be 200 Å or more, and color unevenness due to the step difference (cell gap difference) between the pixel part and the thin film two-terminal element part should be avoided. In order to prevent this from becoming a practical problem, it is desirable that the film thickness be 6000 Å or less, so the thickness of the hard carbon film should be 200 to 6000 Å,
More preferably, the specific resistance is 5×10 6 to 10 13 Ω·cm. The number of device defects due to pinholes in a hard carbon film increases as the film thickness decreases, and becomes especially noticeable below 300 Å (defect rate exceeds 1%);
Uniformity of in-plane distribution of film thickness (and therefore uniformity of device characteristics)
(The accuracy of film thickness control is limited to about 30 Å, and the variation in film thickness exceeds 10%). Therefore, it is more desirable that the film thickness is 300 Å or more. In addition, in order to make the hard carbon film less likely to peel off due to stress, and to lower the duty ratio (preferably 1/1000
(below), it is more desirable that the film thickness be 4000 Å or less. Taking these into consideration, the thickness of the hard carbon film is 300 to 4000 Å, and the specific resistivity is 10.
More preferably, it is 7 to 1011 Ω·cm.

[0017]

EXAMPLES Examples of the present invention will be described, but the present invention is not limited thereto. Example 1 As shown in FIG.
A SiO2 layer (2a, 2b) with a thickness of Å was formed. The amorphous polyarylate film used had a glass transition point of 215° C. and a transmittance of 90% or more at a wavelength of 400 to 850 nm. The SiO2 fabrication conditions were a substrate temperature of 50° C. or lower and a film formation rate of 300 Å/min. This SiO2 film was found to be amorphous by X-ray diffraction and electron beam diffraction. Next, ITO was deposited on SiO2 to a thickness of about 1000 Å by sputtering, and then patterned to form a pixel electrode. Next, an MIM element was provided as follows. First, Al was deposited to a thickness of about 1000 Å by vapor deposition and patterned to form a lower electrode 7. On top of this, a hard carbon film was deposited as an insulating layer 2 to a thickness of about 1000 Å by plasma CVD.
After depositing it to a thickness of Å, it was patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr
CH4 flow rate: 10 SCCMRF power: 0.2 w/cm2 Furthermore, N on top of this
After depositing i to a thickness of about 1000 Å by EB evaporation, it was patterned to form the upper electrode 6.

Example 2 As shown in FIG. 1, 5000 Å thick Si3N4 layers (2a, 2b) were formed on both sides of a 100 μm thick amorphous polyether sulfone film 1 by sputtering. The amorphous polyether sulfone film used had a glass transition point of 223° C. and a transmittance of 84% or more at a wavelength of 400 to 850 nm. Next, ITO was deposited on SiO2 to a thickness of about 1000 Å by sputtering, and then patterned to form a pixel electrode. Next, an MIM element was provided as follows. First, Al was deposited to a thickness of about 1000 Å using a vapor deposition method, and then patterned to form a lower electrode 7. On top of that, a hard carbon film was deposited as an insulating layer 2 to a thickness of about 1000 Å using a plasma CVD method. Patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr
CH4 flow rate: 10 SCCMRF power: 0.2 w/cm2 Furthermore, N on top of this
After depositing i to a thickness of about 1000 Å by EB evaporation, it was patterned to form the upper electrode 6. When a liquid crystal display device was manufactured using the MIM elements manufactured in Examples 1 and 2, good display characteristics were obtained.

Comparative Example 1 Similar to Examples 1 and 2, 6000 Å thick SiO2 layers (2a, 2b) were formed on both sides of a 100 μ thick uniaxially stretched polyethylene terectalate film by sputtering.
was created. The uniaxially stretched polyethylene terectalate film used was found to have crystallinity as a result of X-ray diffraction. Further, the glass transition point was 80° C., and the transmittance at a wavelength of 400 to 850 nm was 83° or more. Next, ITO was deposited on SiO2 to a thickness of about 1000 Å by sputtering, and then patterned to form a pixel electrode. Next, in order to provide the MIM element, first, Al was deposited to a thickness of about 1000 Å by vapor deposition and patterned to form the lower electrode 7. On top of this, a hard carbon film was deposited as the insulating layer 2 by plasma CVD to a thickness of about 1000 Å. After depositing to a thickness of 1000 Å, it was patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr
CH4 flow rate: 10 SCCMRF power: 0.2 w/cm2 Furthermore, N on top of this
When patterning was attempted after depositing i to a thickness of about 1000 Å by EB evaporation, a pattern shift with large anisotropy occurred. Even if the exposure area was made smaller, it was not possible to form a Ni pattern. Furthermore, peeling of the film in the stretching direction and deformation of the pattern due to heat were also observed.

[0020]

[Effects of the Invention] Since the present invention is configured as described above, the thin film laminated device of the present invention is free from substrate deformation, curling, and pattern shift, and can achieve low cost and weight reduction. When a thin film stacked device is made into an MIM type element using a hard carbon film as an insulating layer, the hard carbon film becomes 1
) Because it is produced by a vapor phase synthesis method such as plasma CVD method,
The physical properties can be controlled over a wide range by changing the film forming conditions, and therefore there is a large degree of freedom in device design. 2) Since it is hard and can be made thick, it is less susceptible to mechanical damage, and it is expected that pinholes will be reduced due to thicker film. 3) It is possible to form a high-quality film even at low temperatures near room temperature, so there are no restrictions on the substrate material. 4) It is suitable for thin-film devices because it has excellent uniformity in film thickness and film quality. 5) Since the dielectric constant is low, advanced microfabrication technology is not required, and therefore it is advantageous for increasing the area of the device.Furthermore, the low dielectric constant allows the device to have a high steepness and a high Ion/Ioff ratio, so a low duty ratio can be achieved. Therefore, it is suitable as a particularly reliable switching element for liquid crystal display, and is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a thin film device of the present invention.

[Figure 2] MIM configured by the thin film device of the present invention
FIG. 3 is an explanatory diagram of the main parts of the element.

FIG. 3 is a partially cross-sectional perspective view of a liquid crystal display device incorporating the thin film device of the present invention.

FIG. 4: a is the IV characteristic curve of the MIM device, b is lnI
It is a graph showing a −√v characteristic curve.

FIG. 5 shows a Gaussian distribution according to a 1R spectrum of the hard carbon film used as the insulating layer of the MIM device of the present invention.

FIG. 6 is a spectrum diagram showing the results of an IR absorption spectroscopy analysis of the hard carbon film used as the insulating layer of the MIM element of the present invention.

FIG. 7 is a spectrum diagram showing the results of a Raman spectroscopy analysis of the hard carbon film used as the insulating layer of the MIM element of the present invention.

[Explanation of symbols]

1 Plastic substrate 1' Plastic substrate 2 Hard carbon film 2a Inorganic substance 2b Inorganic substance 3 Liquid crystal 4 Pixel electrode 4' Common electrode 5 Active element (MIM element) 6 Second conductor (bus line) (upper electrode) 7 First
Conductor (lower electrode) 8 Alignment film 9 Gap material

Claims (2)

[Claims] 1. A thin film laminated device with a substrate, characterized in that the substrate is an amorphous plastic with thin films made of an inorganic material formed on both surfaces thereof. 2. The thin film laminated device with a substrate according to claim 1, wherein the plastic substrate has a transmittance of 80% or more in a wavelength range of 400 to 850 nm.