JPH0473764B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid state display device in which a vertical channel type stacked type insulated gate type semiconductor device (hereinafter referred to as IGF) using a single crystal semiconductor on a substrate is provided in a matrix configuration.

The present invention provides a semiconductor device comprising a first conductive electrode, a first semiconductor, a first insulator, a second semiconductor, a second conductive electrode, and a second insulator on a transparent insulating substrate. A third semiconductor formed on the first insulator on two sides of the laminate stacked in layers constitutes a pair of channel forming regions.
Related to providing solid state display devices using IGF.

The present invention uses this laminate and extends from the first conductive electrode to serve as one electrode of the picture element. The second conductive film is disposed in the Y direction, and leads connected to a pair of gate electrodes are disposed in the X direction to form a matrix configuration.

The object of the present invention is to provide a composite semiconductor device having such a matrix structure on a substrate and use it as a display device such as a liquid crystal display type or an electrochromic display type which is a solid state display device.

When providing a flat solid state display device, a liquid crystal solid state display device is known in which a pair of electrodes are provided on parallel light-transmitting substrates, such as glass or plastic plates, and liquid crystal is injected between the electrodes.

Therefore, in order to make this display section into a plurality of picture elements, configure them into a matrix, and turn any picture element into an on or off state by controlling it with a logic circuit of a decoder and driver provided around the picture element, it is necessary to It was necessary to make IGFs, inverters, resistors, etc. that correspond to the picture elements using the same process and structure. A control signal is then given to this IGF to turn on or off the corresponding picture element.

This liquid crystal display or electrochromic display element uses a capacitor (hereinafter referred to as C) as its equivalent circuit.
). For this purpose, IGF and C are arranged in a 2×2 matrix, for example, as shown in FIG.

In FIG. 1, each address of the matrix constitutes one picture element by two IGFs 10 and 10' forming a pair and C70 as a display section.

These are connected to bit lines as columns (Y direction) 51 and 52, and on the other hand, gates are connected to form rows (X direction) 53 and 54 (word lines).

Then, for example, 51 and 54 are set as "1", and 5
When 2 and 54 are set to "0", both IGFs 10 and 10' are turned on, and IGFs at other addresses are turned off. Then, by selecting arbitrary bit lines and word lines one by one and turning them on, the electrically equivalent element C
A display section 70 can be selectively turned on.

The present invention utilizes two
Implementing IGF in a paired configuration (e.g. 10, 10') using both sides of one laminate, the present invention
IGF is used. Traditionally known horizontal channel type
In addition to reducing the area required for IGF wiring other than the display part compared to IGF, when the active picture elements in a solid-state display device are, for example, 640 x 525, the IGF of all the picture elements can operate normally. This is simply impossible when considering the product yield. For this reason, the present invention provides for one of the pair of IGFs.
If the gate of the IGF is damaged, the damaged IGF is separated and removed by laser trimming (hereinafter referred to as LT) from the lead in the X direction.
A so-called redundant element is provided in every picture element. In addition, the gate electrode of this IGF uses a sublimable metal for LT, especially a metal whose main component is chromium, so that the lead in the X direction will not have any problem even when this electrode is used for LT. It is characterized by being a thing.

In addition, since the second conductive film is an electrode of the IGF and is used as a lead wire for the bit line, and the second conductive film and insulator of the laminate can be formed simultaneously in the same stack, the photo line graph It was possible to form a matrix structure by repeating E only four times (three times if the word line leads and gate electrodes were made of the same material).

In this way, by combining the present invention based on its design specifications, it was possible to create a solid-state display device for flat televisions that can replace cathode ray tubes.

FIG. 2 shows a partial sectional view of a perspective view of the solid state display device of the present invention. In the drawing, a transparent insulating substrate 1 made of glass or plastic, a lower electrode 3 of a pixel
6. Laminated body 60 (a part of which is provided with leads in the Y direction by the second conductive film 16), two leads 29 in the X direction, and two IGF gates constituting a pair extending from each other. electrodes 19, 19',
It consists of alignment coatings 30, 32, liquid crystal 70, an upper electrode 33 of a display element, an upper ground electrode 34 made of glass or plastic, and a deflection plate 35. A stacked type on an insulating substrate 1 in such a solid state display device.
The solid-state display device of the present invention is shown below with an enlarged portion of the IGF.

FIG. 3 shows a longitudinal cross-sectional view of a laminated IGF for carrying out the present invention and its manufacturing process.

This figure shows a manufacturing example in which two IGFs are used to drive display picture elements and are manufactured in one laminate, but the same applies to the case where a plurality of IGFs are manufactured on the same substrate.

In the drawings, a first conductive film 2 (hereinafter referred to as E1) is provided on an insulating substrate 1, such as a quartz glass or borosilicate glass substrate, or an organic film, as a lower electrode or one electrode of a picture element. In this embodiment, a transparent conductive film whose main component is tin oxide doped with fluorine is formed to a thickness of 0.3 μm. This was subjected to selective etching using the first mask. Furthermore, on this upper surface, a first non-single crystal semiconductor 3 (hereinafter simply referred to as S1) having a conductivity type of P or N type is placed at
3000A, first insulator 4 (hereinafter simply referred to as S2)
(0.3~3μ), and a third semiconductor 5 (hereinafter simply referred to as S3) having the same conductivity type as the first semiconductor (0.1~3μ).
0.5μ) were stacked (stacked, ie, referred to as S). This lamination creates a NIN, PIP structure (I is an insulator).

On this top surface, ITO (indium tin oxide),
_The second conductive film 6 ( _{hereinafter S5}
Here, a metal (500 to 3000 Å) containing chromium as a main component was used in close contact with the semiconductor, and aluminum was further layered on the top surface to a thickness of 0.5 to 2 μm, for example, 1 μm. Furthermore, a second insulator 7 (hereinafter simply referred to as S5) which is effective as an interlayer insulator is provided on the upper layer.
were laminated to a thickness of 0.5 to 5 μm, for example 1 μm. This insulator is a silicon oxide film, silicon nitride film, or PIQ film made by LP CVD method, PCVD method, photo CVD method, etc.
and other organic resins.

Next, unnecessary portions of this laminate 60 were removed using a second photomask.

The N and P layers of the first and third semiconductors are N ⁺ N or P ⁺ P, and N ⁺ NINN ⁺ , P ⁺ PIPP ⁺ (I is an insulator) are P or N and the first and second electrodes. It was effective to lower the contact resistance.

In this way, the first conductor 12, the first semiconductor 13, the first insulator 14, and the third semiconductor 1
5. A laminate 60 consisting of the second conductor 16 and the second insulator 17 was formed using a mask.

Here, plasma gas phase etching is performed using, for example, HF gas or a mixed gas of CF ₄ + O ₂ at 0.1 to 0.5 torr.
The etching speed was 500 Å/min at 30 W.

After this, these laminates S1, 13, S2, 14,
Intrinsic or P ^- or N ^- that covers S3, 15, conductor 16, and insulator 17 to form a channel forming region
A type of non-single crystal semiconductor was laminated as the third semiconductor 24. This third semiconductor 24 is deposited on the substrate by silane glow discharge method (PCVD method), photo CVD method,
Using the LT CVD method (also called the HOMO CVD method), the
It was installed under the conditions of 200℃, 0.1torr, 30W, 13.56MHz, and is amorphous or semi-amorphous with hydrogen or fluorine added. It uses crystalline silicon semiconductor. The present invention focuses on amorphous or semi-amorphous semiconductors.

Furthermore, in the same reactor, a silicon nitride film 25 is coated with silane (disilane is also acceptable) on the top surface by photo-CVD method without exposing the third semiconductor surface to the atmosphere.
and ammonia by a gas phase reaction using mercury excitation method, and the thickness was 300 to 2000 Å.

This insulating film may be immersed in a nitrogen or ammonia atmosphere activated by electromagnetic energy at a frequency of 13.56 MHz to 2.45 GHz at 100 to 400° C. to form silicon nitride in a solid phase vapor phase reaction.

Alternatively, silicon nitride may be formed by a PCVD method.

Thus, in the vicinity of the S2, 14 sides as shown in FIG. 3B, channel forming regions 9, 9' and an insulator as a gate insulator 25 were formed thereon.
The third semiconductor 24 forms a diode junction with S1 and S3.

In FIG. 3B, a third conductive film 18 having a thickness of 0.3 to 1 μm was then formed to cover the laminate.

The conductive film 18 was a light-transmitting conductive film such as ITO (indium tin oxide), tin oxide, or indium oxide, or a heat-resistant and sublimable conductive film containing Si, Mo, and Cr as main components.

Here, we achieved this by using a two-layer film of ITO (1000 Å) and a metal whose main component is chromium. Silicon semiconductor doped with a large amount of N-type phosphorus impurity
It may be formed to a thickness of 0.1 to 0.5μ, for example 0.3μ, by the PCVD method. For example, a non-single-crystalline semiconductor with a thickness of 0.4 μm, to which 1% phosphorus was added, and which was microcrystalline (grain size 50 to 300 Å) was fabricated by the PCVD method. Furthermore, aluminum is laminated to a thickness of 0.5 to 3μ, for example 1.5μ, by vacuum evaporation on the top surface, and the sheet resistance is 0.1Ω/
□ Below.

Thereafter, a resist was formed on the upper surface, and the aluminum for the word line (X direction) 51 shown in FIG. 4 was etched using a third mask. Furthermore, gate electrodes 19 and 19' were formed by etching using a fourth mask.

Thus, Figure 3C was obtained. Of course lead wire 5
If 1 and a gate electrode are used together, this mask is processed in the same way as in .

As is clear from FIG. 3C, the two IGFs 10 and 10' using both sides of the stacked body 60 have two channels 9 and 9', and a source or drain 13 and a drain or source 15. , gates 19 and 19'.

That is, in the drawing, two IGFs could be provided as a pair.

Thus, the source or drain can be connected to S1, 13,
S4, 24 having channel forming regions 9, 9', drain or source are formed by S3, 15, and a gate insulator 2 is formed on the side surface of the channel forming region.
5. It was possible to fabricate a pair of laminated IGFs 10 and 10' with gate electrodes 19 and 19' provided on their outer surfaces.

Furthermore, in the IGF of the present invention, the electron mobility is 5 to 30 times higher than that of holes, so it is preferable to use an N-channel type. Furthermore, it is effective to configure a pair of P-channel IGFs on other parts of the substrate to form complementary transistors.

In this invention, the channel length is determined by the thickness of S2, 14, and is generally 0.1 to 3μ, here 1.0μ.
And so. Due to such a short channel, the mobility of the non-single crystal semiconductor 25 is 1/5 to 1/100 of that of a single crystal.
Despite this, the dual transistors were able to have cut-off frequency characteristics of over 10MHz.

Thus, drain 15 or 13, source 1
3 or 15, as gate 19 or 19'
We were able to obtain V _DD = 5V, V _GG = 5V, and an operating frequency of 17.5MHz.

FIG. 4 is a plan view of a portion of the solid-state display device of the present invention shown in FIG. 1 using the IGF shown in FIG. 3.

Figure 4 A is 1, 1, 1, 2, 2, 1 of Figure 1,
In particular, the IGF of addresses 1 and 2 corresponds to addresses 2 and 2.
FIG. Furthermore, Figure 4B is B of Figure 4A.
-B' is a vertical cross-sectional view. Also, A- in Figure 4A
The longitudinal cross-sectional view of A' corresponds to FIG. 3C. The electrode (fourth electrode) extending from the lower electrode 12 of this IGF
) 36 provided on the lower side in the figure is connected to a liquid crystal (capacitor) 70 composed of picture elements. The other is provided as the installation electrode 32 for the liquid crystal 70.

In FIG. 4, the gate electrodes 19 and 19' provided along the stacked body 60 are connected to the leads 5 in the X direction provided perpendicularly to the stacked body 60.
It is connected to 3. The second conductive film 51 provided inside the stacked body 60 was configured as a lead wiring in the Y direction. In this way, it was possible to have a matrix configuration in the X and Y directions and a 1Tr/pixel structure.

Furthermore, as is clear from FIG. 4, this display could be manufactured by photoetching five times (three times for the element alone). Previously 7
However, with the configuration of the present invention, this number can be reduced by two times. Further, the area required for the IGF of the display of the present invention is 1% or less of the total area.

The display area was 91% and the lead area was 8%. The present invention
When manufacturing a large 20-inch display,
With current mask manufacturing technology, the minimum line width of the mask is
It becomes 25μ. However, the present invention requires such 25μ
While using this as a lead in the X and Y directions,
IGF has the great advantage that the channel length is 1μ or less and is not subject to mask accuracy limitations. Since the IGF has a short channel length, the area required for the IGF on the substrate can be reduced, and the accuracy of photolithography does not limit the upper limit of the operating frequency.

Furthermore, since these picture elements operate at high frequencies, the frequency characteristics of IGF are extremely important.
The IGF of the present invention was able to have a cutoff frequency of 10 MHz or more (17.5 MHz) (N-channel IGF) at V _DD = 5 V and V _GG = 5 V. V _th =0.2~
2V was made possible by controlling the concentration of impurities added to S4 and 25.

If one of the gate electrodes in the pair of IGFs is shot like this, the entire panel can be removed by irradiating a laser beam from above, such as a YAG laser light with a Q switch, to sublimate and vaporize the gate electrode. The yield has been reduced to 3% from the previous
We were able to improve the yield from a state where there were only 5 or fewer defective picture elements (defective picture elements are considered good) to 40%. In addition, laser light (here with a wavelength of 1.06μ) is
(using a YAG laser) or with a diameter of 10-30μ. However, since the gate electrodes of the pair of IGFs of the present invention were separated by 30 μm, the pixels on the shot side of one of the IGFs could be removed without any hindrance to the other IGFs in the pair.

Furthermore, the number of masks required for manufacturing is sufficient, and it has many features such as not requiring mask precision, in addition to the fact that the channel length can be extremely short to 0.2 to 1 μ.

Moreover, the IGF overcoat polyimide resin 26 allows the liquid crystal 70 to fill only the picture element portion. In addition, two electrodes 3 are placed around the picture element.
6, 33 (see Figure 2) spacer (thickness 1~
In addition, this spacer was used to make the peripheral area of the picture element black (non-reflective) and used as a black matrix. By creating a black matrix, we were able to improve the contrast of this picture element. Furthermore, a display element such as a GH (guest host) type liquid crystal is filled in the area 31, and this picture element is turned on and off when IGF10 and 10' are turned on.
Control was performed by turning it off.

In the present invention, the distance between the two electrodes 30 and 32 which have been subjected to alignment treatment for the liquid crystal 31 is 1 to 10 μm, for example, GH type liquid crystal is injected into the gap, and in addition, red, green, This display can be displayed in color by embedding a yellow filter. Then, the three elements of red, green, and yellow may be arranged alternately.

Also, reverse leakage is caused by S1 as shown in Figure 1.
Or S3 to SixC _1-x (0<x<1 e.g. x=0.2)
By setting S2 to Si ₃ N _4-x (0<x
<4) or SixC _1-x (0<x<1) to make it an insulator, reducing the amount of impurities in S1 and S3 flowing into S2, reducing the leakage of this N-I junction or P-I junction. Even if 10V is applied in the opposite direction,
It was below 10nA/ ^cm2 . This was 2 to 3 orders of magnitude lower than the reverse leakage of single crystals, and was preferable due to active use of the physical properties unique to non-single crystal semiconductors. Furthermore, when operating at high temperatures, the metal of the electrode is likely to mix into the non-single crystal S1 _and S3 and cause defects, so the side close to this electrode is ).
As a result, the device was operated at 150°C for 1,000 hours, and no malfunctions were found after evaluating 1,000 devices.
This is an extremely high improvement in reliability, considering that if S1 or S3 were formed of only amorphous silicon in close contact with this electrode, it would not withstand 150°C for 10 hours.

Furthermore, because of such a laminated IGF, it has become possible to fabricate a plurality of IGFs, resistors, and capacitors on a substrate, especially an insulating substrate, without using conventional high-precision photolithography technology. It became possible to develop it into a liquid crystal display.

In the present invention, it is effective to use a semiconductor as the second laminate and use the periphery of this side as a channel forming region. However, although such a structure has the advantage that there is no process for forming the third semiconductor, in such a case, the surface of this semiconductor is exposed to an etching atmosphere, so that the interface state density is lower than that of the method using the third semiconductor described above. It has the disadvantage that it is larger than the other IGFs, and variations occur between each IGF.

The non-single crystal semiconductor in the present invention is silicon, germanium or silicon carbide (SixC _1-x 0<x<1),
Silicon carbide or silicon nitride was used as the insulator.

[Brief explanation of the drawing]

FIG. 1 shows an equivalent circuit of a solid-state display device according to the present invention having a matrix structure in which an insulated gate type semiconductor device and a capacitor are used as picture elements. FIG. 2 is a perspective view of the solid state device of the present invention. FIGS. 3A, 3B, and 3C are longitudinal cross-sectional views showing the steps of the stacked insulated gate type semiconductor device of the present invention. FIGS. 4A and 4B are longitudinal sectional views of a solid-state display device showing a flat display in which the stacked insulated gate semiconductor device of the present invention, a capacitor, and a display portion are integrated.

Claims (1)

[Claims] 1. A first semiconductor, a first insulator, and a second semiconductor on a first electrode having a transparent conductive film on a transparent insulating substrate.
a laminate including a semiconductor, a second conductive film, and an interlayer insulator, the first and second semiconductors constitute a drain and a source, and a third laminate adjacent to both sides of the laminate is provided. A channel forming region is formed of a semiconductor, and a gate insulating film and two gate electrodes are disposed on both sides of the laminate on the third semiconductor, thereby forming first and second insulated gate type semiconductor devices. an electrode extending from the first electrode constitutes one electrode of the picture element,
A solid-state display device, wherein the two gate electrodes are connected to leads in the X direction, and the second conductive film is connected to leads in the Y direction. 2. A solid-state display device according to claim 1, characterized in that the gate electrode is provided with a sublimable metal as a main component.