JPS59139772A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To obtain good electrical characteristics with miniature structure and a small amount of power consumption for a solid-state image pickup device made of an amorphous material containing H and a photoelectric converting material containing mainly Si, by setting the amounts of Si larger than a prescribed ratio and H within a certain range for said amorphous material. CONSTITUTION:A thin SiO2 film of about 800Angstrom is formed on a p type Si substrate 20, and an Si3N4 film 22 of about 1,400Angstrom is formed at a prescribed position on the SiO2 film. Then a p-diffusion region 23 is formed at the upper part of the substrate 20 by an ion implantation process in order to secure better separation of each element. Then Si is partially oxidized in an atmosphere of H2 and O2 (1:8) to form an SiO2 layer 24. Both films 22 and 21 are deleted, and a gate insulated film 25 of an MOS transistor TR is formed with SiO2. Then a poly-Si gate part 26 is formed together with diffusion regions 27 and 28. An SiO2 film 29 is formed over the regions 27 and 28 with addition of a drain electrode 31 and a source electrode 33. In this case, the amorphous material contains >=50 atom % Si and 10-50 atom % H respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to improvement of a light receiving device or a solid-state imaging device manufactured on a semiconductor single crystal substrate.

[Background of the invention]

The imaging device conventionally used is an imaging tube of the type that operates in an accumulation mode and scans a photoconductive target with an electron beam. In this case, since an electron beam is used,
There are drawbacks such as the need for high voltage and the difficulty of miniaturization. Solid-state imaging devices or imaging plates have been devised to overcome these difficulties.

FIG. 1 shows the principle of a solid-state imaging device. Each picture element 4 is arranged in a grid pattern and read out one by one using the XY addressing method. Selection of each picture element is performed by a horizontal scanning signal generator 1 and a vertical scanning signal generator 2. 3 is a switch section connected to each picture element, and 5 is an output end.

Specific configurations of the photoelectric conversion section of each picture element include an example in which a diffusion region is directly formed on the SL substrate, and an example in which four photoconductive films are used.

However, an example in which a photoelectric conversion section is formed by forming a diffusion region on a Si substrate has the following serious disadvantages in practical use.

In order for a solid-state imaging device to have a resolution comparable to that of an image pickup tube, the number of pixels must be 500×400 or more. The smallest picture element size is 20μm x 20μm
Since it is difficult to reduce the thickness to less than 1 cm, the thickness of the Si substrate is approximately 1 cm x 1 cm or more, resulting in an extremely large IC. As the chip size increases, the yield decreases. The cost disadvantage is significant.

In addition, each picture element is generally composed of a photoelectric conversion section (above: corresponding to the diffusion region to the S1 substrate mentioned above) using a MOS switch's source region, but this two-dimensionally arranged MOS switch has a considerable area. This is not a good idea when it comes to configuring the light-receiving surface.

Furthermore, since the wiring lines running vertically and horizontally also run on the surface of the diode, the incident area of light is reduced. These 3% lead to a decrease in the intensity of light j, and the signal output becomes smaller, so the signal to Wj and sound ratio (S
/N ratio).

On the other hand, in an example using a photoconductive thin film, a scanning circuit for performing XY addressing such as the MOS switch is formed on a Si substrate, and a photoconductive thin film is arranged three-dimensionally on the upper layer to form a light receiving section. It is something to do.

An example of such a solid-state imaging device is disclosed in Japanese Patent Publication No. 51-95720. FIG. 2 shows a sectional view for explaining the principle. Diffusion region 7 in Si substrate 6
, 8 are provided to serve as the source and drain of the MOS switch. 10 is a gate H[<t of a MOS switch, 5 is a drain electrode for taking out a signal, and 16 is a source electrode. A photoconductive thin film 17 and a transparent electrode 17 are formed on the switch circuit thus configured. In addition, 13
is an insulator layer.

The electrode 16 is made of, for example, Sb2S3. CdS, As2Se2
A capacitance C corresponding to the area S of the electrode is formed between the transparent conductive thin film 18 and the photoconductive thin film 18 made of a photoconductive substance such as polycrystalline Si. Since the electrode patterns are separated and placed in a matrix, the capacitors are arranged in a matrix. Since this capacitor has a photoconductive thin film in between, it functions as a photosensitive element and forms a picture element. If the photosensitive element is covered with a front circuit, it can be represented by a parallel connection of a variable resistor R whose electrical resistance changes depending on the intensity of light and a capacitor C.

The size of the capacitance C is determined by the polarization area S and the four photoconductive films.The size of the resistance is inversely proportional to the intensity of light incident on the electrode surface at that position, and if no light hits the electrode surface, the Generally, R≠■ depends on the type of conductive thin film.

Since a target voltage (VT) is applied to the transparent electrode 18, the capacitance of the portion not exposed to light during one field maintains the same voltage VT.

Since the resistance R of the portion exposed to light decreases according to its intensity, the charge stored in the capacitor iC is discharged, and the voltage held in the capacitor decreases in proportion to the amount of light.

If the voltage remaining after discharging during one field period is UT, then the voltage is V. A current flows through a charge corresponding to -U, and when charging is completed, the target pressure is raised again. The charging current at this time becomes a video signal corresponding to this field.

[The purpose of the invention and Shigeyasu]

In such a solid-state imaging device, the image transport characteristics such as spectral sensitivity characteristics, resolution, signal-to-noise ratio, and afterimage characteristics are of course important, but for this reason, the heat resistance and mechanical strength of the photoconductive thin film are extremely costly. In other words, it is safe to attach a photoconductive thin film on a Si substrate (!: It is safe to attach a transparent electrode, but when using BN 02 (Suzunesa) as a transparent electrode, it is necessary to It is necessary to heat the substrate after 250°C even when using a transparent electrode.This is the reason why the heat resistance of the light guide film is not so good.A translucent metal thin film can also be used in place of a transparent electrode. In this case, it is not safe to heat the substrate.However, due to reflection and absorption by the metal thin film, the photosensitivity, which is an important characteristic for imaging, decreases significantly, which is undesirable. This is a particular problem in devices.In other words, in a typical one-quadrant imaging target, a NESA electrode is first attached to a glass face plate, and then a photoconductive thin film is attached, so the presence or absence of heat resistance is determined at least during the manufacturing process.
That's not a problem.

Mechanical strength is also a military expense. After applying the photoconductive thin film, it is safe to attach the NESA electrode, and in the case of a color image pickup plate, repeat the process of attaching the filter, and from the viewpoint of ease of handling, the strong mechanical seal absorbs water.

Further, it is assumed that the photoconductive film has a specific resistance of 10 Ω·Cn1 or more. This is because it is reassuring that the charge pattern will not diffuse and disappear within the time interval during which a specific picture element is scanned, that is, the accumulation time.

When polycrystalline Si is used for a photoconductive thin film, it has a particularly low resistivity and there is no need to worry about dividing the film into a mosaic pattern, which complicates the process and reduces the yield rate.

Furthermore, photoconductive films of Sb2S3 and As2Se34 have problems in mechanical strength and heat resistance, and are not suitable for practical use in the imaging device having the structure shown in FIG.

The present invention solves the drawbacks of the above-mentioned prior art.

The basic structure is similar to that illustrated in FIG. 2, in which the front part of the scanning circuit is formed on a Si substrate, and a photoconductive thin film is placed on top of this.

In particular, the present invention is characterized by the use of an amorphous material mainly composed of silicon containing hydrogen as the light-guiding film. In particular, an amorphous material containing 50 atomic % or more silicon and 10 atomic % to 50 atomic % hydrogen is preferable. In this case, a portion of silicon in the amorphous material can be replaced with at least a portion of germanium or carbon, which are homologous elements. The amount of replacement is 60% of silicon.
% is useful.

A film thickness of 0.05 μm or more is used. Practically 0.2μm~
4 μm is often used. Furthermore, the thin film may be multilayered or the composition may be continuously changed.

In this way, an amorphous film containing silicon and hydrogen at the same time is an excellent material that can easily be made to have a high resistivity of 10 Ω・cm or more, and has very few trap levels that hinder the movement of carriers. .

The photoconductive material of the present invention can be manufactured by various methods. Typical examples will be explained below.

The first method is a reactive sputtering method.

FIG. 3 shows a schematic diagram of an apparatus used in the reactive sputtering method. The device itself is a general sputtering device. 101 is a container that can be evacuated, 102 is a sputter target, 103 is a sample substrate, 104 is a shutter, 105 is an input from a high frequency oscillator for sputtering, 106
107 is a heater for heating the substrate, and 1108 is a water cooling device for cooling the substrate.
is a high-purity hydrogen inlet, 109 is an argon temple gas inlet, 110 is a gas reservoir, 111 is a pressure gauge, 112 is a vacuum gauge,
113 is a connection port to the exhaust system.

As a target for sputtering, a target cut from molten silicon may be used. Further, in the case of an amorphous material containing silicon, germanium, or carbon, a target containing a combination of these three types of group (I) elements is used. In this case, for example, it is convenient to use a graphite or germanium γ piece as a target on a silicon substrate. The composition of the amorphous material can be controlled by appropriately selecting the area ratio of silicon to germanium or carbon. Of course, conversely, for example, a silicon thin piece may be provided on a carbon substrate. Further, the target may be constructed by juxtaposing both materials, or a melt of the same composition may be used.

In addition, as a target for spuck, for example, Sl containing phosphorus (P), As, and Boron (B) in advance can be used.
By using these elements, it is possible to introduce these elements as impurity elements.

By this method, an amorphous material of any conductivity type, such as n-type or p-type, can be obtained. In addition, doping with such impurities (thus, it is possible to change the resistance value of the material. A high resistance of about 1013 Ωcm can also be achieved. A method of mixing diborane or phosphine is also possible.

By using the above-mentioned apparatus, a high frequency discharge is generated in an Ar atmosphere containing hydrogen (H2) at various mixing ratios of 30 mol% or less, and Si and graphite are sputtered and deposited on a substrate. A thin layer can be obtained. The pressure of this Ar atmosphere containing hydrogen may be within any range as long as glow discharge can be maintained, and is generally 0.
．． 001 to 1, approximately OTorr is used. 0.1-1.
It is particularly stable at 0 Torr. The temperature of the sample substrate is preferably selected between room temperature and 300°C. 150～
250°C is the most practical. This is because at too low a temperature it is difficult to introduce hydrogen into the amorphous material, and at too high a temperature hydrogen tends to be released from the amorphous material. The concentration of hydrogen contained is controlled by controlling the hydrogen partial pressure in the Ar atmosphere.

When the amount of hydrogen in the atmosphere is 5 to 7 mol %, a content of about 30 atomic % can be realized in the amorphous material. For other compositions, it is sufficient to set the hydrogen partial pressure roughly using this ratio as a guide. Hydrogen components in the material were determined by mass spectrometry of the hydrogen gas generated by heating.

Note that it is difficult to replace Ar in the atmosphere with another rare gas such as Kr.

Further, in order to obtain a film with high resistance, a magnetron-type low-temperature, high-speed sputtering apparatus is preferable.

A second method of manufacturing the amorphous material of the present invention is a method using glow discharge. It is formed by performing a glow discharge of SiH4 to decompose organic matter and deposit it on the substrate. Further, in the case of an amorphous material containing Si and C, a mixed gas of Si and CH4 may be used. In this case S
r kL4 (!: The pressure of the mixed gas of CH4 is O11
The 0-G constant release range maintained between ~5 Torr may be achieved by a DC bias method or a high frequency discharge method. Also s 81) 1
By changing the ratio of the mixed gas of CH4 and CH4, S
The ratio of i and C can be controlled. In order to obtain a high quality amorphous material, it is safe to maintain the substrate temperature between 200''C and 400C.

To create a p-type or n-type amorphous material, add B2H6゜PH3% each to a mixture of SiH4 and CI (4).
This can be carried out by mixing 0.1 to 1% (volume ratio) of . Furthermore, the amorphous film of the present invention can also be produced by electron beam evaporation in an atmosphere containing H2.

[Embodiments of the invention]

Embodiment 1 FIG. 4 to FIG. 10 are device cross-sectional views showing a method of manufacturing a solid-state imaging device of the present invention. The switch circuit and scanning circuit section formed on the semiconductor substrate are manufactured using normal semiconductor device processes. As shown in FIG.
Then, on this 5 inz film, a Si3N4 film 2 of about 1400λ was placed at a predetermined position. A p diffusion region 23 is formed from the upper part of the silicon substrate by 7° ion implantation. FIG. 5 shows this state. This diffusion region 231 was provided to better isolate each element. Next 1. Horse in N:
Silicon was locally immersed in acid in a 0□:1:8 atmosphere, and S
An iO2 layer 24 is formed (FIG. 6). This method is generally called LOGO8 and is a local oxidation method of silicon for element isolation. - support, Si3N4 film 22 and Si
The O2 film 21 is removed and the gate insulating film 25 of the MOS transistor is formed as a 5in2 film.

Next, a gate portion 26 and diffusion regions 27 and 28 are formed using polysilicon (FIG. 7), and then Si is formed on top of this.
O2 film 29 total 29. Then, openings for the electrodes of the source 27 and drain 28 are opened in this film by etching (FIG. 8). AJ of 800 mm as the drain electrode 31
0 people will be deposited. Further, a 5-in2 film 32 is formed for 7,500 μm, and then A, / is deposited on the source electrode 33 to a thickness of 1 μm. FIG. 9 is a sectional view showing this state. Note that the electrode 33 is connected to the regions 27, 28 . The reason for this is that the gate portion is formed to be wide so as to enclose it. This is undesirable because it causes pluming when light enters the signal processing region between the element isolation diffusion layers 23.

Further, some of the shift registers disposed around the device may have a general configuration as illustrated in FIG. 11, for example.

In this example, a two-phase dynamic shift register consisting of a pair of inverter circuits and a pair of delay circuits provides stable operation regardless of the phase of the clock pulse that shifts the scanning pulse. When a start pulse (■0) is input, each bit terminal sequentially generates a shift pulse (■) synchronized with the clock pulse CP2. 11■02... is output.

FIG. 12 shows the timing of this operation.

Of course, the specific circuit configuration of the shift register is not limited to this. In this way, the omnivorous circuit to lOS transistor section is completed. A light receiving section is formed above this MOS) transistor section. Figure 13 shows Si
The top view of a base part is shown.

41 is a contact hole for an electrode.

Next, the semiconductor substrate 40 prepared by the previous steps
is attached to a magnetron type sputtering device. The apparatus is as shown in FIG. The atmosphere is a mixed gas of Ar and hydrogen.7. 'L'orr'.

The hydrogen content is 6 mol%. Silicon is used as the sputter target. Frequency 13.56M) lz.

Reactive sputtering is performed with an input of 300 W to deposit an amorphous silicon thin film 35 containing hydrogen to a thickness of 500 nm on the semiconductor substrate 40 (FIG. 10). The hydrogen content in this amorphous thin film is 20 at%, and the specific resistance is 5X10
“It was Ω・cm.

A first electrode for bias voltage is provided on the top of the amorphous silicon thin film 35.
There are 8 types of electrodes. Since it is safe to let light enter from the top, this electrode is made transparent. Since the heat resistance of amorphous silicon is 300"C, we used a Nesa electrode made of In 20 g. Cr-Au was deposited using a mask on a part of the Nesa electrode that was not the light-receiving area, and wire bonded there to create a bias. Next, in the same way as in a normal semiconductor device, a 5g2 electrode is formed using an Au film or the like on the back surface of the semiconductor substrate 40. In this way, a solid-state imaging device is completed.

Note that 37 in Figure g10 indicates incident light.

The solid-state imaging device produced by the method described above makes it possible to obtain a good screen without pluming.

Example 2 Photoconductive thin film A solid-state imaging device was manufactured using the materials shown in Table 1. The manufacturing procedure is similar to that described in Example 1.

Furthermore, the spectral sensitivity characteristics can be improved by adopting the following configuration as the photoconductive thin film.

First, one layer of an amorphous silicon film containing 25 atomic percent hydrogen was prepared.
μ, then 20 at% hydrogen, 20 at% germanium
, an amorphous material consisting of 60 atomic percent silicon, and 2 atomic percent hydrogen.
Layers of amorphous materials each having a thickness of 0.5 μm are formed, each having a thickness of 0 atomic %, 30 atomic % carbon, and 50 atomic % silicon. The formation method was based on the above-mentioned reactive sputtering method. Furthermore, it is placed in a vacuum evaporation apparatus and CeO2 is deposited to a thickness of 10 nm using a resistance heating method. Finally, gold was deposited to a thickness of 25 nm.

If gold has a thickness of this level, the light transmittance can be 60% or more, and sufficient light reinforcement can be obtained.

Si02. instead of CeO2 in the above example. TiO2
Good results were also obtained by depositing . 100 to 300 people were used as the J sample.

Example 3 On an n-type silicon substrate (similar to Example 1, a shift register using MOS transistors and a switching MO8
Manufacture FETs. The basic structure is the same as that of the first embodiment. However, since the substrate is n-type, this depends on the structure of the p-type channel. This may be done by following a well-known semiconductor IC manufacturing method.

Hydrogen-containing amorphous silicon was deposited on the SI substrate on which the scanning circuit had been prepared in this manner by a glow bombardment method. The discharge atmosphere is 5i)L, 1.5 Torr. The substrate was heated to 0.5 MHz, the high frequency input was 0.5 MHz, the pressure was 0.0 Torr, the substrate temperature was 300°O, and an amorphous material was deposited.The thickness of the amorphous material was 2 .mu.m, and a specific resistance of 1.times.10.sup.12 .OMEGA..cm.NESA electrodes were formed using ■n2o3 on this amorphous material, and a solid-state imaging device was manufactured.

Embodiment 4 This example uses a CCD (Charge Couple) as a scanning circuit.
-pledDevice) transfer area is used.

FIG. 14 shows a plan view of the arrangement of Taniyasumoto.

50 is a horizontal clock terminal, 51 is a vertical clock terminal, 5
2 is an output horizontal transfer register, 53 is a vertical transfer gate, 5
4 is a vertical analog transfer register, and 55 is a picture element portion in which a diffusion region and an MO8 type switch using this as a source are combined.

FIG. 15 is a cross-sectional view of the CCD transfer area, and FIG. 16 is a cross-sectional view of the picture element portion.

In FIG. 15, an electrode 62 is placed on a Si substrate 61 via an insulating layer.
．． 63 is formed and a two-phase clock voltage is applied through 64.65. This causes the potential well within the SI substrate to move and charge transfer to occur. FIG. 16 is a cross-sectional view of the light-receiving area, that is, the picture element, where 71 is a diffusion layer;
2 is an insulating layer, 73 is a metal electrode, 74 is a gate, 75 is a photoconductive film, and 76 is a transparent electrode. The 15th light receiving area
The CCD transfer area shown in the figure is subsequently formed.

The transparent electrode 76, the photoconductive film 75, the metal 1, and the other 73 form a light receiving section, and the switch region that moves carriers induced here to the transfer region has a gate 74, forming a substantial MOS switch. are doing.

Si that formed the CCD transfer area and the MOS switch and switch parts.
A substrate is prepared and attached to a magnetron type sputtering device. The atmosphere was a mixed gas of Ar and hydrogen at 0.2To.
rr and wake up. The hydrogen content is 6 mol%. The sputter target was silicon.

Note that the valley elements, ie, the CCD transfer area, the MOS switch section, etc., configured on the Si substrate can be manufactured by a method known up to now.

Reactive sputtering is performed at a frequency of 13.56 M1 (z) and an input of 300 W to deposit an amorphous material upper film 75 containing hydrogen to a thickness of 500 nm on the light receiving part of the Si substrate. The hydrogen content was 20 atomic %, and the specific resistance was 5 x 1013 Ωcm.1n203
A NESA electrode is formed on this amorphous material. Cr--Au was vapor-deposited using a mask from a part of the negative electrode, and wire bonded thereto to provide a bias electrode.

The operation will be simply explained using FIG. 14. When light hits the light receiving section through the transparent electrode, carriers induced by this optical signal are vertically transferred by applying a voltage to the gate electrode between the diffusion region in the light receiving section 55 and the vertical analog transfer register 54. It is moved to register 54. The vertical transfer register is a CCD driven through a two-phase vertical clock terminal 51, and is sent column by column through a vertical transfer gate 53 to an output horizontal transfer register 52. This horizontal transfer register is also a CCD driven through a two-phase horizontal clock terminal 5o, and charges corresponding to the signal are sent to the output and taken out as a signal output. The transfer of the horizontal transfer register is completed within the period of the voltage pulse applied to the vertical transfer gate.
The frequency of the two-phase drive should be selected so that the

〔Effect of the invention〕

The imaging device of the present invention explained using the above embodiments has the characteristics of good matching of spectral Ill with visual sensitivity, good sensitivity and noise characteristics, high resolution, no blooming, no blurring, and low power consumption. It also has the characteristics of being small, lightweight, and highly reliable, and has extremely large industrial effects.

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle of a solid-state imaging device, Figure 2 is a cross-sectional view of a pixel part of a solid-state imaging device using a photoconductive thin film, and Figure 3 is a diagram showing the principle of a solid-state imaging device.
The figure is an explanatory diagram of a reactive sputtering device, FIG. 4 to FIG. 10 are main part sectional views showing the manufacturing process of the solid-state imaging device of the present invention, FIG. 11 is a diagram showing an example of a shift register, and FIG. 12 13 is a plan view of the solid-state imaging device of the embodiment, FIG. 14 is an explanatory diagram of the embodiment using COD as a scanning circuit, and FIG. 15 is a diagram showing the operation timing of the shift register.
1) A sectional view of the transfer area, and FIG. 16 is a sectional view of the light receiving section. In the figure, 1...Horizontal scanning signal generator, 3...Vertical scanning signal generator, 3...Switch unit, 4...-Picture element,
5.Output end, 6,20...Semiconductor base handling,
7, 8, 27°28...diffusion area, 10.26.
Gate electrode, 13.29.32・Insulating layer, 16.3
3..First conductive layer, 17.35..Light guide Hiroshi J
]8゜36 Transparent electrode. Figure 1 Figure 4 Figure 5 Figure 4 Figure 7 Figure 8 Figure 70 Figure 73 Figure 1/Figure 12 Figure 14 Continued from page 1 0 Inventor Keiken Imamura Kokubunji Hitachi, Ltd. Central Research Laboratory, 1-280 Higashi Koigakubo, Kokubunji City, Hitachi, Ltd. Author Akira Sasano 1-280 Higashi Koigakubo, Kokubunji City Hitachi, Ltd. Central Research Laboratory Author: Seiji Kubo 1-280 Higashi Koigakubo, Kokubunji City Hitachi, Ltd. 0 in the Central Research Laboratory Author: Norio Koike 1-280 Higashi-Koigakubo, Kokubunji City 0 in the Central Research Laboratory, Hitachi, Ltd. Author: Shusaku Nagahara In the Central Research Laboratory, Hitachi, Ltd., 1-280 Higashi-Koigakubo, Kokubunji City

Claims (1)

[Scope of Claims] 1. A photoelectric conversion section comprising a light-transmitting electrode disposed on the top of a photoelectric conversion material layer of a scanning hand that sequentially selects a plurality of optical and electrical conversion sections; The material is mainly silicon,
In a solid-state imaging device made of an amorphous material containing hydrogen,
A solid-state imaging device characterized in that the amorphous material contains 50 atomic % or more of silicon and 10 atomic % to 50 atomic % of hydrogen. It has at least a photoelectric conversion material layer on the upper part, and a photoelectric conversion part in which a transparent electrode is arranged on the upper part of the photoelectric conversion material layer, and the photoelectric conversion material is mainly made of silicon and contains hydrogen. A solid-state imaging device made of an amorphous material, wherein the amorphous material has a specific resistance of 1010 Ωc. 3. A semiconductor substrate having at least a scanning means for sequentially selecting a plurality of photoelectric conversion parts, at least a photoelectric conversion material layer on the top of the semiconductor substrate, and a transparent electrode arranged on the top of the photoelectric conversion material layer. In the solid-state imaging device, the photoelectric conversion material is an amorphous material mainly composed of silicon and containing hydrogen, wherein part of the silicon in the amorphous material is germanium,
A solid-state imaging device characterized in that the least amount of carbon is partially replaced. 4. A semiconductor substrate having at least a scanning plane for sequentially selecting a plurality of photoelectric conversion parts, at least a photoelectric conversion material layer on top of this semiconductor substrate, and a light-transmitting electrode arranged on top of this photoelectric conversion material layer. In a solid-state imaging device having a photoelectric conversion section, wherein the photo-illuminated material is an amorphous material mainly composed of silicon and containing hydrogen: the photo-electric conversion material layer is composed of a multilayer thin film. A solid-state imaging device characterized by: