JP2835580B2 - Semiconductor device for driving a flat light valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat-type light valve device used for a direct-view display device or a projection display device, for example, an active matrix liquid crystal panel. More specifically, the present invention relates to a semiconductor device which is incorporated as a substrate of a liquid crystal panel and has electrodes and switching elements for directly driving liquid crystal.

[0002]

2. Description of the Related Art The principle of an active matrix device is simple: a switching element is provided for each pixel, the corresponding switching element is turned on when a specific pixel is selected, and turned off when it is not selected. It is something to keep in a state. This switching element is formed on a glass substrate constituting a liquid crystal panel. Therefore, a technique for making the switching element thinner is important. Usually, a thin film transistor is used as the switching element.

Conventionally, in an active matrix device, a thin film transistor is formed on the surface of a silicon thin film deposited on a glass substrate. Generally, a field effect insulated gate transistor is used as such a transistor. This type of transistor includes a channel region formed in a silicon thin film, and a gate electrode formed so as to cover the channel region. By applying a predetermined voltage to the gate electrode, the conductance of the channel region is controlled to perform a switching operation.

[0004]

However, in the conventional insulated gate thin film transistor, even if the gate region is controlled to make the channel region non-conductive, a leak current flows through the back surface of the thin film into the channel region. There was a problem that would. The so-called back channel,
There is a problem that normal operation of the active matrix device is hindered. That is, in order to operate each pixel line-sequentially at high speed, the conductance ratio between the conducting state and the non-conducting state of each switching element is required to be 10 ⁶ or more. However, the switching performance required for this back channel is obtained. I can't do things.

On the other hand, even if the back channel can be eliminated, since the semiconductor device is used under light irradiation, when light enters from outside into the channel region of the thin film transistor, its conductance increases, and It becomes a leak current in the drain / source in the conductive state. There is also a problem that the ratio between the leak current and the leak current when light is not irradiated increases as the quality of the semiconductor thin film forming the channel region becomes higher as in a single crystal.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention provides a planar light source including a thin film transistor having a structure capable of effectively preventing a back channel and blocking incident light. It is an object to provide a valve driving semiconductor device.

In order to achieve the above object, a semiconductor device according to the present invention comprises: an insulating support substrate made of a light-transmitting material;
It is formed using a substrate having a stacked structure including a light-shielding thin film disposed on the support substrate and a semiconductor thin film disposed on the light-shielding thin film via an insulating film. A transparent electrode for driving a light valve, that is, a pixel electrode is disposed on the support substrate. Further, a switching element for selectively exciting the pixel electrode is formed. The switching element comprises a field effect insulated gate transistor having a channel region and a main gate electrode for controlling conduction in the channel region. A channel region is formed in the semiconductor thin film, and a main gate electrode is formed so as to cover the channel region. A light shielding layer is formed separately from the main gate electrode. The light-shielding layer is made of the light-shielding thin film, and is arranged on the opposite side of the main gate electrode with respect to the channel region. That is, the transistor has a structure in which the channel region is sandwiched between the main gate electrode and the light shielding layer from above and below.

Preferably, the main gate electrodes disposed on both sides of the transistor channel region are made of a light-shielding material, and the channel region and the light-shielding layer are almost completely shielded from external incident light. More preferably, the light-shielding layer is made of a conductive material, and eliminates a back channel. In addition, a current can be applied to the light shielding layer to control the back channel. More preferably, the channel region of the transistor is formed of a semiconductor thin film made of silicon single crystal, and can be processed on the order of submicron using a normal LSI technology.

[0009]

In the semiconductor device for driving a flat light valve having the above-mentioned structure, the conductance of the channel region of the transistor constituting the switching element is controlled by a pair of main and sub gate electrodes from both surfaces of the semiconductor thin film via the insulating film. You. Therefore, unlike a conventional thin film transistor, which is controlled by one gate electrode only from one side, no back channel is generated. In other words, the sub-gate electrode according to the present invention is provided to suppress the back channel.

In addition, since the channel region is covered by a pair of light-shielding gate electrodes from above and below, light incident on the light valve device passes through the pixel electrode, and is almost completely blocked in the channel region. The generation of current is effectively prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic partial sectional view of a semiconductor device for driving a flat light valve. As shown in the figure, the present device has a laminated structure 2 formed on a support substrate 1.
The laminated structure 2 includes a light-shielding thin film and a semiconductor thin film disposed on the light-shielding thin film via an insulating film. A transparent electrode for driving a light valve, that is, a pixel electrode 3 is formed on the surface of the composite substrate having the laminated structure 2. And the laminated structure 2
Is provided with a switching element 4 for selectively exciting the pixel electrode 3. Switching element 4
Has a drain region 5 and a source region 6 formed apart from each other in a semiconductor thin film. The drain region 5 is connected to the signal line 7, and the source region 6 is connected to the corresponding pixel electrode 3. Further, a channel region 7 is provided between the drain region 5 and the source region 6.
A main gate electrode 9 is formed on the surface side of the channel region 7 via a gate insulating film 8. The main gate electrode 9 is connected to a scanning line (not shown) and controls the conductance of the channel region 7 to perform an on / off operation of the switching element 4. On the back side of the channel region 7, a light-shielding layer 11 is disposed via an insulating film 10.
That is, the light shielding layer 11 is arranged on the opposite side of the main gate electrode 9 with respect to the channel region 7. The light-shielding layer 11 is made of the light-shielding thin film described above. When the light-shielding thin film is simultaneously conductive, the light-shielding layer 11 also serves as a sub-gate electrode for controlling the back channel.

Since the pair of main and sub gate electrodes 9 and 11 arranged on both sides of the channel region 7 are made of a light-shielding material, light incident on the channel region 7 is completely blocked. Further, in this embodiment, the channel region 7 is formed in a semiconductor thin film made of silicon single crystal, and the normal LSI processing technology can be directly applied, so that the channel length can be reduced to the order of submicron. It is.

FIG. 2 is a schematic partial sectional view of a composite substrate used for manufacturing a semiconductor device for driving a flat light valve according to the present invention. As shown in the figure, the composite substrate includes a support substrate 1 and a laminated structure 2 formed thereon. First, the support substrate 1 is made of a light-transmitting insulating material, for example, heat-resistant quartz containing silicon oxide as a main component or aluminum oxide. Aluminum oxide is excellent in that it has a thermal expansion coefficient close to that of silicon and hardly generates stress. or,
Since a single crystal can be formed, a single crystal semiconductor film can be heteroepitaxially grown thereon. Next, the laminated structure 2 includes a light-shielding thin film 21 disposed on the support substrate 1,
An insulating film 22 disposed on the light-shielding thin film 21;
Semiconductor thin film 23 made of a single crystal material adhered to
And The light-shielding thin film 21 is made of a conductive material, for example, polysilicon. Alternatively, instead of the single-layer film of polysilicon, a single-layer film of germanium, silicon-germanium, or silicon, or a multilayer film of silicon containing at least one layer of germanium or silicon-germanium can be used. Further, a metal film of silicide, aluminum, or the like can be used instead of these semiconductor materials. When aluminum oxide, that is, sapphire, is used as the supporting substrate, a silicon single crystal heteroepitaxially grown thereon may be used as a light-shielding film.

The laminated structure 2 includes a support substrate 1 and a light-shielding thin film 2.
1 may include a base film 24 interposed therebetween. The base film 24 is provided for improving the adhesion between the support substrate 1 and the laminated structure 2. For example, when the support substrate 1 is made of quartz containing silicon oxide as a main component, silicon oxide can be used as the base film 24. When the underlying film also has a function of blocking impurities from the support substrate 1, the insulating film is made of silicon nitride or oxynitride, or a multilayer film of at least one of them and silicon oxide. In particular, oxynitride is useful because the stress can be adjusted.

Next, the insulating film 22 is used later as a gate insulating film for the sub-gate electrode formed of the light-shielding thin film 21, and is made of, for example, silicon oxide or silicon nitride. Alternatively, the insulating film 22 can be composed of a multilayer film of silicon nitride and silicon oxide.

Semiconductor thin film 2 located on top of laminated structure 2
3 is made of, for example, silicon. As this silicon, a single crystal, polycrystal or amorphous material can be used. Since an amorphous silicon thin film or a polycrystalline silicon thin film can be easily deposited on a glass substrate using a chemical vapor deposition method, it is suitable for manufacturing an active matrix device having a relatively large screen. When an amorphous silicon thin film is used, an active matrix liquid crystal device having an area of about 3 inches to 10 inches can be manufactured. In particular, since an amorphous silicon thin film can be formed at a low temperature of 350 ° C. or lower, it is suitable for a large-area liquid crystal panel. When a polycrystalline silicon thin film is used, a small liquid crystal panel of about 2 inches can be manufactured.

However, when a polycrystalline silicon thin film is used, when a transistor having a channel length on the order of submicrons is formed by applying a fine semiconductor processing technique, the reproducibility of element constants is poor and the variation is large.
Furthermore, in the case of amorphous silicon, a high-speed switch cannot be expected even if submicron processing technology is used. On the other hand, when a semiconductor thin film made of silicon single crystal is used, the fine semiconductor processing technology can be directly applied, the integration density of switching elements can be significantly improved, and an ultra-fine light valve device can be obtained. it can.

Even if the switching element has a channel length on the order of microns, the channel mobility is large, so that high-speed operation is possible. Further, peripheral circuits for controlling these switching elements can be integrated on the same supporting substrate with high sensitivity, and the switching element array can be controlled at high speed, so that they are indispensable for high-definition moving image display.

Next, with reference to FIGS. 3 and 4, a method of manufacturing the semiconductor device for driving a flat light valve according to the present invention will be described in detail. First, in the step shown in FIG. 3A, a composite substrate is prepared. That is, the supporting substrate 1 made of a polished quartz plate
First, a base film 24 made of silicon oxide is formed by chemical vapor deposition or sputtering. A light-shielding thin film 21 made of polysilicon is deposited on the base film 24 by using a chemical vapor deposition method. Subsequently, an insulating film 22 made of silicon oxide is formed on the light-shielding thin film 21 by using a thermal oxidation method or a chemical vapor deposition method. Finally, a semiconductor thin film 23 made of silicon single crystal is formed on the insulating film 22.
To form This semiconductor thin film 23 is obtained by adhering a single crystal silicon semiconductor substrate to the insulating film 22 and then polishing it to a thickness of several μm.

The single crystal silicon semiconductor substrate used is L
It is preferable to use a high-quality silicon wafer used for SI manufacturing, and its crystal orientation is “100” 0.0 ± 1.
It has a uniformity in the range of 0 °, and its single crystal lattice defect density is not more than 500 defects / cm ² . First, the surface of a silicon wafer having such physical characteristics is precisely smoothed. Subsequently, the silicon wafer and the support substrate 1 are thermocompression-bonded to each other by superposing and heating the smoothed surface on the insulating film 22. By this thermocompression bonding, the silicon wafer and the support substrate 1 are firmly fixed to each other. In this state,
The silicon wafer is polished until it has a desired thickness. Note that an etching process may be performed instead of the polishing process. Since the silicon single crystal semiconductor thin film 23 thus obtained retains the quality of the silicon wafer substantially as it is, it is possible to obtain a semiconductor substrate material having extremely excellent crystal orientation uniformity and lattice defect density.

The following steps are more preferable because some electrical defects remain on the thermocompression-bonded surface of the silicon wafer with the current technology. That is, thermal oxidation or C
SiO ₂ is formed by VD. Subsequently, polysilicon is formed by CVD, and surface polishing is performed if necessary. Then turn to form a SiO ₂ by a silicon nitride film and the thermal oxide or CVD by SiO _2, CVD by thermal oxidation or CVD. This silicon wafer is placed on a quartz support substrate or CV
D, thermocompression bonding on a quartz support substrate coated with SiO ₂ , and polishing of the silicon wafer.

Next, in the step shown in FIG. 3B, the laminated structure 2 excluding the underlayer 24 is sequentially etched, and the light-shielding layer 11 made of the light-shielding thin film 21 is formed on the lowermost layer, that is, on the underlayer 24.
To form At this time, a gate oxide film 10 made of an insulating film 22 is also formed on the light shielding layer 11 at the same time. The formation of the light-shielding layer 11 can be obtained by covering the entire surface of the composite substrate with the photosensitive film 26, patterning the photosensitive film 26 into a desired shape, and selectively performing etching using the patterned photosensitive film 26 as a mask.

Subsequently, in a step shown in FIG. 3C, an element region 25 is formed on the two-layer structure of the patterned light shielding layer 11 and the gate oxide film 10. Element region 25
Can be obtained by selectively etching only the semiconductor thin film 23 into a desired shape. This etching is performed by selectively etching the semiconductor thin film 23 using the photosensitive film 26 patterned according to the shape of the element region as a mask.

Further, in the step shown in FIG. 3D, a thermal oxide film forming process is performed on the entire surface including the surface of the semiconductor thin film 23 exposed after the removal of the photosensitive film 26. As a result,
On the surface of the semiconductor thin film 23, a gate oxide film 8 is formed. Subsequently, in the step shown in FIG.
5, a polycrystalline silicon film is deposited by a chemical vapor deposition method. The polycrystalline silicon film is selectively etched using a photosensitive film (not shown) patterned in a predetermined shape to form a main gate electrode 9. This main gate electrode 9
Are arranged on the semiconductor thin film 23 via the gate oxide film 8.

In the step shown in FIG. 4F, impurity ions are implanted through the gate oxide film 8 using the main gate electrode 9 as a mask to form the drain region 5 and the source region 6 in the semiconductor thin film 23. . As a result, a transistor channel region 7 in which impurities are not implanted is provided below the main gate electrode 9 between the drain region 5 and the source region 6.

Subsequently, in the step shown in FIG.
A protective film 27 is formed so as to cover the element region. As a result,
The switching element including the light shielding layer 11 and the main gate electrode 9 is embedded in the protective film 27. Finally, in the step shown in FIG. 4H, a part of the gate oxide film 8 on the source region 6 is removed to form a contact hole, and the transparent pixel electrode 3 is formed so as to cover this part. The pixel electrode 3 is made of, for example, a transparent material such as ITO. In addition, since the protective film 27 disposed below the pixel electrode 3 can be made of, for example, silicon oxide, it is transparent, and further, the support substrate 1 made of quartz glass disposed therebelow.
Is also transparent. Therefore, the three-layer structure including the pixel electrode 3, the protective film 27 and the quartz glass support substrate 1 is optically transparent and can be used for a transmission type light valve device.

Conversely, a pair of main and sub gate electrodes 9 and 11 sandwiching the channel region 7 from above and below are made of polysilicon and are optically opaque, so that incident light can be blocked and leakage current flowing to the channel region can be prevented. ing. In order to completely shut off, use a material with a low band gap such as silicon or germanium.

As described above, in the manufacturing method shown in FIGS. 3 and 4, a film forming process using a high temperature of 600 ° C. or more and a high resolution It is possible to form a field-effect insulated gate transistor having a micron-order or sub-micron-order size by performing a chiriso etching and an ion implantation process. Since the silicon single crystal film used is of extremely high quality, the obtained insulated gate transistor has excellent electrical characteristics. At the same time, the pixel electrode 3 can also be formed in a micron-order size by a miniaturization technique, so that a semiconductor device for an active matrix liquid crystal having a high-density and fine structure can be manufactured.

FIGS. 3 and 4 show the embodiment in which the single crystal semiconductor film 23 is formed by a thermocompression bonding method. 5 and 6 show an embodiment in which a single crystal semiconductor film is formed not by thermocompression bonding but by an epitaxial method.
This will be described with reference to FIG.

First, a transparent aluminum oxide 101 such as sapphire is used as a support substrate as shown in FIG. Next, as shown in FIG.
The silicon single crystal film 102 is heteroepitaxially grown using the above crystal as a seed. Aluminum oxide, when polycrystalline, has a coefficient of thermal expansion closer to that of silicon than quartz. Therefore, when polycrystalline aluminum oxide is used for the supporting substrate of the embodiment shown in FIG. 3, the thermal stress is small, and the crystallinity of the single crystal silicon film formed thereon is reduced by the high temperature treatment of the semiconductor process. Can be maintained through

In FIG. 5, since single crystal aluminum oxide is used, the single crystal silicon film 1 is formed as shown in FIG.
02 can be heteroepitaxially grown. Next, the grown single crystal silicon film 102 is patterned as shown in FIG.

Next, an insulating film 110 is formed as shown in FIG. 5 (D), and a hole 112 is made in a part of the insulating film 110 to expose the surface of the single crystal silicon film 111 as shown in FIG. 5 (E). Next, an amorphous or polycrystalline semiconductor film 123 is formed as shown in FIG. In the hole 112, the single crystal silicon film 111 and the semiconductor film 123 are in contact. When high-temperature heat treatment is performed in this state, the semiconductor film 123 laterally grows using the single crystal silicon film 111 in the hole as a seed. Therefore, FIG.
For (G), the region 123A near the hole is monocrystallized. The region 123B that is not single-crystallized is in a polycrystalline state. In this epitaxial growth, the example in which the polycrystalline semiconductor film 123 is formed first and the lateral epi growth is performed by heat treatment in FIG. 6F is shown. However, the gas source epitaxial growth or the liquid phase epitaxial growth is performed from the state of FIG. However, a single crystal semiconductor film can be formed as shown in FIG. As the semiconductor film, silicon, Ga
As films are possible.

Next, as shown in FIG. 6H, a region 124 to be a substrate of the transistor is patterned. Next, a gate insulating film 108 is formed as shown in FIG. 6I, and finally, as shown in FIG.
A transistor connected to the transistor 06 is formed. Source area 1
Channel region 107 between the gate region 05 and the drain region 106
Of the gate electrode 125 and the light shielding film 111
Can be controlled by In FIG. 6 (J), the light shielding film 1
Although the example in which 11 is connected to the source region 105 is shown, it is not necessary. In FIG. 6 (G), the lateral epi growth
Since a sufficiently long single crystal region is formed at 3 to 5 μm, FIG.
As in (J), a single crystal transistor can be formed over the insulating film.

Finally, an example of a light valve device assembled using the flat type light valve driving semiconductor device according to the present invention will be described with reference to FIG. As shown in the figure, the light valve device includes a semiconductor device 28, a counter substrate 29 disposed opposite the semiconductor device 28, and an electro-optical material layer such as a liquid crystal layer 30 disposed between the semiconductor device 28 and the counter substrate 29. It is composed of In the semiconductor device 28, a pixel electrode or a drive electrode 3 for defining a pixel and a switching element 4 for exciting the drive electrode 3 according to a predetermined signal are formed.

The semiconductor device 28 includes a support substrate 1 made of, for example, quartz glass and a laminated structure 2 formed on the support substrate 1.
It consists of In addition, a polarizing plate 31 is adhered to the back side of the support substrate 1. The switching element 4 is formed on a single-crystal silicon semiconductor thin film included in the multilayer structure 2. The switching element 4 includes a plurality of field effect insulated gate transistors arranged in a matrix. The source region of the transistor is connected to the corresponding pixel electrode 3, the main gate electrode is connected to the scanning line 32, and the drain electrode is connected to the signal line 7. The semiconductor device 28 further includes an X driver 33 and is connected to the column-shaped signal lines 7. Further, it includes a Y driver 34 and is connected to the row-shaped scanning lines 32. The opposite substrate 29 is a glass substrate 35
And a polarizing plate 36 bonded to the outer surface of the glass substrate 35
And a counter electrode or common electrode 37 formed on the inner surface of the glass substrate 35.

Although not shown, the light shielding layer or the sub-gate electrode included in each switching element 4 is also preferably connected to the scanning line 32 in common with the main gate electrode. With such a connection, it is possible to effectively prevent a leak current flowing in the channel region of the transistor forming the switching element. Alternatively, the light shielding layer can be connected to the source region or the drain region of the corresponding transistor. In any case, by applying a predetermined voltage to the light shielding layer, it is possible to effectively prevent a leakage current based on the back channel. Further, the threshold voltage of the channel region can be set to a desired value by controlling the voltage applied to the light shielding layer.

Next, the operation of the light valve device having the above configuration will be described in detail with reference to FIG. The main and sub gate electrodes of the individual switching elements 4 are commonly connected to a scanning line 32, and a scanning signal is applied by a Y driver 34 to control conduction and interruption of the individual switching elements 4 in line order. The data signal output from the X driver 33 is applied via the signal line 7 to the selected switching element 4 in the conductive state. The applied data signal is transmitted to the corresponding pixel electrode 3 and excites the pixel electrode to act on the liquid crystal layer 30 to make the transmittance substantially 100%. On the other hand, at the time of non-selection, the switching element 4 becomes non-conductive, and maintains the data signal written in the pixel electrode as electric charge. The liquid crystal layer 30 has a high specific resistance and normally operates as a capacitive element.

The on / off current ratio is used to express the switching performance of these switching elements 4. The current ratio required for the liquid crystal operation can be easily obtained from the writing time and the holding time. For example, when the data signal is a television signal, 90% or more of the data signal must be written within about 60 μsec of one scanning line period. On the other hand, 90% or more of the electric charge must be held in one field period of about 16 msec. As a result, the current ratio needs to be 5 digits or more. In this regard, according to the present invention, the channel region has a structure in which the conductance is controlled from both surfaces by the main and sub gate electrodes, so that the leak current at the time of off is substantially completely removed. The ON / OFF ratio of the switching element having such a structure can sufficiently secure 6 digits or more. Therefore, it is possible to obtain an active matrix type light valve device having an extremely high-speed signal response.

[0039]

As described above, according to the present invention, the pair of main and sub gate electrodes disposed on both sides of the transistor channel region are made of a light-shielding material such as polysilicon so that the channel region is protected from external incident light. There is an effect that it is possible to effectively cut off and effectively prevent the generation of a leak current based on the photoelectric effect. Furthermore, since the transistor channel region formed in the semiconductor thin film is controlled from above and below by a main gate electrode and a light-shielding layer made of a conductive material, that is, a sub-gate electrode, a so-called back channel can be effectively prevented. A thin film transistor having an excellent on / off ratio can be obtained. As a result, there is an effect that a flat-type light valve driving semiconductor device excellent in high-speed response and without malfunction can be obtained. In addition, by forming a switching element composed of a field-effect insulated gate transistor on a semiconductor thin film made of silicon single crystal, it is possible to obtain an ultrafine and ultrahigh-density flat-panel light valve driving semiconductor device. There is also an effect.

[Brief description of the drawings]

FIG. 1 is a schematic partial cross-sectional view showing a structure of a flat plate type light valve driving semiconductor device.

FIG. 2 is a schematic partial cross-sectional view showing a structure of a composite substrate used for manufacturing such a semiconductor device.

FIG. 3 is a schematic process diagram showing a manufacturing process of the semiconductor device for driving a flat light valve.

FIG. 4 is a schematic process diagram showing a manufacturing process of the semiconductor device for driving a flat light valve.

FIG. 5 is another schematic process view showing the manufacturing process of the flat plate type light valve driving semiconductor device.

FIG. 6 is another schematic process view showing the manufacturing process of the semiconductor device for driving a flat light valve.

FIG. 7 is a schematic exploded perspective view showing the structure of a light valve device formed using a flat plate type light valve driving semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support substrate 2 Laminated structure 3 Pixel electrode 4 Switching element 5 Drain region 6 Source region 7 Channel region 8 Gate oxide film 9 Main gate electrode 10 Gate oxide film 11 Light shielding layer 21 Light shielding thin film 22 Insulating film 23 Semiconductor thin film 24 Base film

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshikazu Kojima 1-8-1, Nakase, Mihama-ku, Chiba-shi, Chiba Inside Seiko Electronic Industries Co., Ltd. (72) Hiroaki Takasu 1-8-1, Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Mitsuo Kawamoto, Examiner, Electronic Industry Co., Ltd. (56) References JP-A-58-8883 (JP, A) JP-A-61-79256 (JP, A) JP-A-4-133303 (JP, A) US Pat. No. 4,751,196 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 29/786 H01L 21/336 H01L 27/12 G02F 1/136 500

Claims (3)

(57) [Claims] 1. A composite having a laminated structure including a transparent support substrate, a light-shielding thin film disposed on the transparent support substrate, and a semiconductor thin film disposed on the light-shielding thin film via an insulating film. A substrate, having at least the light-shielding thin film on the composite substrate.
A light valve driving transparent electrode disposed on the upper part have, the semiconductor thin film in a channel region and said channel region contact
A drain region and a source region, a switching element for selectively energizing said transparent electrode consists of a transistor having a main gate electrode for controlling conduction of said channel region, said channel said light shielding thin film The main game
A plurality of switching elements are arranged in an array,
The channel region of each switching element has a crystal orientation of “10
0 ”single crystal silicon with uniformity in the range of 0.0 ± 1.0 °
A semiconductor device for driving a flat light valve made of a recon thin film . 2. Between the light-shielding thin film and the transparent support substrate.
2. An undercoat layer comprising oxynitride.
The flat panel type light valve driving semiconductor device as described in the above. 3. The transparent supporting substrate mainly comprises silicon oxide.
The light-shielding thin film and the transparent support
Having an underlayer made of silicon oxide between the substrates.
2. The semiconductor device for driving a flat light valve according to claim 1.