JP2827514B2 - Photoelectric conversion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion device, and more particularly to a photoelectric conversion device having a superlattice structure. More specifically, the compound semiconductor gallium arsenide (GaAs) is made of a quantum well layer, and aluminum gallium arsenide (AlGaAs).
Using a semiconductor material with a wide energy band gap such as GaAs / AlGaAs with a
For infrared detection utilizing the fact that electrons excited from the ground state flow as a tunnel current in the upper part, which is thinned by the strong electric field of the barrier layer, and change the electrical conductivity of the superlattice structure due to infrared rays that resonate with the band transition. In the photoelectric conversion device, excellent in the sensitivity characteristics, infrared charge transfer device (IRC
The present invention relates to a structure of a photoelectric conversion device for realizing a photoelectric conversion element having multiple pixels such as CD).

[0002]

2. Description of the Related Art In a conventional photoelectric conversion element using an intersubband transition, only an infrared component parallel to a superlattice surface among incident infrared rays is detected in resonance with the intersubband transition. If infrared light is vertically incident on the sensing element like a device, infrared light cannot be detected.
As shown in FIG. 10, a gallium arsenide (GaAs) layer of a compound semiconductor is a quantum well layer on the bottom surface of a light transmitting substrate 5 that transmits infrared rays of a tetrahedron, and aluminum gallium arsenide (AlGaAs) is provided.
As shown by an arrow A, infrared rays are incident on the superlattice surface 1A of the superlattice structure 1 in which the layers are alternately stacked as barrier layers.

Signals from the respective superlattice structures 1 are provided by placing bumps (pillars) 3 made of indium (In) on the superlattice structure 1 and similarly mounting In bumps on the signal input portions. Face bonding is performed with the signal processing chip 4 made of Si, electrical connection is taken, and the signal processing chip multiplexes and reads. In order to detect infrared rays using a photoelectric conversion device having such a conventional structure, it is necessary to apply a high voltage between the electrodes, so that a large amount of dark current easily flows, and this dark current is suppressed. To lower the operating temperature below the liquid nitrogen temperature,
The structure is such that the height and width of the barrier layer are increased.

[0004]

In a photoelectric conversion device having a conventional structure as shown in FIG. 10, when an infrared image is to be obtained, a focal plane (detection element surface) is required with respect to the optical axis of the infrared light. ,
That is, since the superlattice plane 1A is not perpendicular, there is a disadvantage that a complicated optical system is required. In the device having such a structure, since the composition of the AlGaAs layer serving as the barrier layer is not varied and laminated, the wavelength of the resonating infrared rays is limited. 6, which has the disadvantage that the wavelength range that can be detected is narrow.

In addition, since infrared rays cannot be made incident on the superlattice surface 1A in parallel, only a part of the incident infrared rays can be used, and there is a problem that the photoelectric conversion efficiency is reduced. The unused infrared rays are reflected on the surface of the In bump or the Si signal processing chip and become stray light, which causes a problem such as generation of a ghost in the infrared image. Applying a bias voltage to the superlattice structure increases the dark current and lowers the signal-to-noise ratio. In addition, there is a problem that the response wavelength shifts to a shorter wavelength side in the method of increasing the height and width of the barrier layer.

[0006] In addition, a charge storage type photoelectric conversion device usually requires a signal charge storage section having a large area to store a large amount of signal charges. However, in practice, the area that can be secured on a signal processing chip is limited. Therefore, there is a problem that the sensitivity is consequently limited. Also, the fact that the wavelength range that can be detected is narrow is not preferable because only a part of the incident infrared light can be used and the photoelectric conversion efficiency decreases.

An object of the present invention is to provide a superlattice-type photoelectric conversion device in which a focal plane (detection element surface) can be configured to be perpendicular to an optical axis while making infrared rays incident on a superlattice plane as parallel as possible. It is another object of the present invention to provide a superlattice-type photoelectric conversion device in which infrared rays not absorbed by the superlattice structure do not become stray light. Furthermore, the present invention provides a superlattice-type photoelectric conversion device in which the area of the superlattice structure is miniaturized while having the same function as a photoelectric conversion device having a large superlattice structure in order to reduce dark current. In addition, by changing the thickness of the quantum well layer of the superlattice structure portion, the barrier height of the barrier layer, the thickness, etc. during the formation of the superlattice, a superlattice type photoelectric device having a desired spectral sensitivity and spectrum can be obtained. It is an object to provide a conversion device.

[0008]

According to the present invention, there is provided a photoelectric conversion device having a superlattice structure in which thin layers of different semiconductors are alternately deposited a plurality of times. In the photoelectric conversion device to be detected, a superlattice structure is formed in an island shape on a light transmitting substrate through which infrared light having a wavelength to be detected is transmitted, and at least one of peripheral end surfaces of the island-shaped superlattice structure is formed. 30 with respect to the superlattice surface of the superlattice structure
An inclined surface having an angle from 60 degrees to 60 degrees, and the inclined surface is a reflecting surface that reflects infrared light incident from the light transmitting substrate side.

Also, of the peripheral end surfaces of the island-shaped superlattice structure, the end surface facing the reflection surface is provided with an opaque film through which infrared light propagated from the superlattice structure is not transmitted or from the superlattice structure. A non-reflective film that does not transmit the reflected infrared light and hardly reflects the light. In addition, infrared light does not pass through at least one of the surface of the island-shaped superlattice structure facing the light-transmitting substrate and the gap of the island-shaped superlattice structure where the light-transmitting substrate is exposed, and It is characterized in that a non-reflective film that is hardly reflected is provided.

The anti-reflection film is formed by three layers of a conductive semi-transparent thin film layer, a transparent layer made of a dielectric, and a reflective layer made of a metal when viewed from the light transmitting substrate side. Is used as an individual electrode or a ground electrode necessary for detecting infrared rays in the superlattice structure portion, or as a part of both electrodes. Further, a light transmitting plate having a plurality of convex portions on the surface is arranged on the opposite side to the surface on which the island-shaped superlattice structure is formed, so as to be parallel to the light transmitting substrate. Further, a plurality of projections are formed on the surface of the light transmitting substrate opposite to the surface on which the island-shaped superlattice structure is formed.

[0011] Further, the present invention is characterized in that the convex portion is formed in a wavy shape in a semicylindrical shape. Further, in order to accumulate signal charges generated by infrared rays detected by the superlattice structure portion, in a gap portion between the island-like superlattice structure portion on the surface of the light transmitting substrate on the side where the island-like superlattice structure portion is formed. And a line switching switching circuit for sequentially reading out the signal charges in the signal charge storage unit.

In addition, by continuously changing the thickness of the quantum well layer of the superlattice structure portion and the barrier height and thickness of the barrier layer during the formation of the superlattice structure portion, the wavelength band of infrared light that can be detected is expanded. It is characterized by having done.

[0013]

In the apparatus of the present invention, as shown in FIG. 1, a superlattice structure 12 is formed in an island shape on a light transmitting substrate 11 through which infrared light having a wavelength to be detected is transmitted. One surface of the peripheral end surface 13 of the lattice structure portion 12 is formed as an inclined surface 13 having an angle of θ = 45 degrees with respect to the superlattice surface 14 of the superlattice structure portion 12, and the inclined surface 13 is formed from the light transmitting substrate 11 side. As shown by an arrow A, it is used as a reflection surface 13 that reflects the incident infrared light.

Accordingly, as shown in FIG. 1, the infrared light incident on the reflecting surface 13 from the light transmitting substrate 11 side is incident on the superlattice structure 12 substantially parallel to the superlattice surface 14. Further, the sensing element surface can be configured as a surface perpendicular to the optical axis of the incident infrared light. As shown in FIG. 2, an opaque film 16 or a non-reflective film 35 is formed on the end surface facing the reflection surface 13 so that the surface of the superlattice structure portion 12 facing the light transmitting substrate 11 and the island-like super lattice The anti-reflection film 35 is also formed at a position where the surface of the light transmitting substrate 11 is exposed in the gap between the structural parts 12. Therefore, infrared rays that are not absorbed by the superlattice structure part 12 are incident on the adjacent superlattice structure part, or infrared rays incident on parts other than the superlattice structure part are reflected by the Si signal processing chip or the like and become stray light. I'm preventing.

Further, as shown in FIG. 3, the anti-reflection film 35 is viewed from the light transmitting substrate 11 side, and a conductive semi-transparent thin film layer 17 of a metal thin film, a transparent layer 18 of a dielectric or the like, a reflection layer of metal or the like.
By forming the three-layer structure of 19, the infrared light reflected by the conductive translucent thin film layer 17 and the infrared light reflected by the reflective layer 19 can be canceled by the interference effect, so that the reflection of infrared light is prevented. be able to.

The phase difference between the two reflected lights is determined by the thickness of the transparent layer 18.
By adjusting the angle to 180 degrees and adjusting the attenuation of the infrared intensity in this film with the thickness of the conductive semi-transparent thin film layer 17, the intensity of both reflected light is matched, so that both reflected light are canceled by interference. Can fit. Further, the conductive semi-transparent thin film layer 17 can also be used as an individual electrode. As shown in FIG. 4 (a), the light transmitting substrate 11 has a plurality of projections 21 on the surface opposite to the surface on which the island-shaped superlattice structure 12 is formed so as to be parallel to the light transmitting substrate 11. A plate 22 is provided, or a plurality of convex portions 21 are formed on the surface of the light transmitting substrate 11 opposite to the surface on which the superlattice structure 12 is formed, as shown in FIG.

With such a structure, the incident infrared light is focused on the minute reflecting surface 13 of the superlattice structure portion 12, so that the incident infrared light can be efficiently introduced into the superlattice structure portion 12. Thus, the light receiving sections sparsely arranged in the focal point can function as if they occupy most of the focal plane. That is, the dead area between the sensing elements can be almost eliminated.

As shown in FIG. 5, when the convex portion 21 is formed in a semi-cylindrical shape with a rectangular bottom portion, the reflecting surface 13 can be made to look like a rectangle close to a square when viewed from the infrared ray incident side. Therefore, the dead area can be minimized. In addition, by introducing the above structure, the superlattice structure 12 can be made smaller or smaller, so that the dark current when a constant bias voltage is applied can be reduced substantially in inverse proportion to the area of the superlattice structure 12. Become.

By doing so, the superlattice structure 12 can be made smaller, and as shown in FIG. 6, the storage gate electrode 23, the insulating film 24,
A plurality of signal charge accumulating portions 26 such as capacitors constituted by the potential wells 25 are formed, and signal charges generated by infrared rays detected by the superlattice structure portion 12 can be accumulated.

Although not shown, it is possible to provide a switching circuit connected to a line selection circuit such as a MOS switching array for switching a signal read line, thereby simplifying the structure on the signal processing chip side. You can also. In particular, as shown in FIG. 7, it is not necessary to dispose a signal processing chip in opposition to the superlattice structure 12 without using bumps, and around the superlattice structure 12 that detects infrared rays, Since the signal can be read only by arranging the line selection circuit, the multiplexer circuit, and the like, the structure of the detection device can be greatly simplified.

As shown in FIG. 8, in the process of forming the superlattice of the superlattice structure, the thickness of the quantum well layer 31 made of GaAs,
In the device of the present invention in which the height, the thickness, and the like of the barrier layer 32 composed of the Ga _1-x Al _x As layer are continuously changed during the formation, the maximum response wavelength (λ _p ) varies with the thickness or the thickness of the quantum well layer. Since it can be controlled by the barrier height and thickness of the barrier layer, a spectral sensitivity characteristic curve 41 as shown in FIG. 9 is obtained, and a photoelectric conversion device capable of efficiently performing photoelectric conversion of incident infrared light is obtained. .

[0022]

FIG. 1 is a diagram showing a first embodiment of the apparatus of the present invention.
As shown in the figure, a heavily doped GaAs layer or the like for a ground electrode is deposited on a light transmitting substrate 11 made of GaAs or the like through which infrared light having a wavelength to be detected is transmitted, using a molecular beam epitaxial method or the like. A superlattice structure 12 is formed by alternately depositing thin layers of different semiconductors such as a GaAs layer and a Ga _1-x Al _x As layer a plurality of times by molecular beam epitaxy.

Next, one surface of the peripheral end surface of the superlattice structure portion 12 left in the form of an island is etched by photolithography or the like so that phosphoric acid () in which the (111) A surface appears with respect to the etching of the GaAs (100) surface. H ₃ PO ₄ ): Superlattice surface 14 of superlattice structure 12 using an anisotropic etching solution of hydrogen peroxide (H ₂ O ₂ ) = 1: 10.
To an inclined surface with an angle of about 45 degrees. Next, a transparent insulating film such as zinc sulfide (ZnS) and a reflective film made of an aluminum (Al) film or the like are formed on the inclined surface by laminating them in a two-layer structure, and reflect infrared light incident from the light transmitting substrate 11. The reflection surface 13 is formed by processing.

An individual electrode 33 for signal reading is also formed on the top of the superlattice structure portion 12 by Al evaporation or the like, and finally an In bump 34 for face bonding is formed. FIG. 2 is a view showing a second embodiment of the device of the present invention. The surface of the island-like superlattice structure 12 facing the reflection surface 13 is made of ZnS or the like which does not transmit infrared light propagated from the superlattice structure 12 side. An opaque film 16 composed of a transparent insulating film and an Al film, or an anti-reflection film 35 as described below, which does not transmit infrared light transmitted from the side of the superlattice structure portion 12 and is hardly reflected, I have.

The light transmitting substrate 11 of the island-like superlattice structure 12
A non-reflective film 35, which does not transmit infrared light and hardly reflects light, is formed on the surface facing the surface and the gap between the island-shaped superlattice structure 12 where the substrate is exposed. FIG. 3 shows the antireflection film of the present invention.
35 is an explanatory view of the structure of FIG. 35, when viewed from the light transmitting substrate 11, a conductive semi-transparent thin film layer 17 of a metal thin film such as chromium (Cr) or nickel (Ni), a transparent layer 18 of a dielectric material such as ZnS, The reflective layer 19 is formed of three layers of a metal film such as Al. Then, an electrical connection can be made to the conductive translucent thin film layer 17 so that it can be used as a necessary electrode for detecting infrared rays in the superlattice structure.

FIG. 4 is an explanatory view of the light incident portion of the device of the present invention. In FIG. 4 (a), the superlattice structure portion 12 is parallel to the light transmitting substrate 11 on the side opposite to the island-shaped surface. Multiple convex parts on the surface
A light transmission plate 22 having 21 is arranged. This light transmission plate 22
Is made of a material having a high refractive index such as germanium (Ge), and the convex portion can be formed by sagging during etching or by mechanical polishing.

In FIG. 4B, a plurality of projections 21 are formed on the surface of the light transmitting substrate 11 opposite to the surface on which the superlattice structure 12 is formed. In any case, the projection is formed at a position opposite to the light receiving surface (reflection surface) of the superlattice structure 12. Further, the shape of the convex portion 21 may be formed in a semi-cylindrical shape (ridge) having a rectangular bottom surface as shown in the embodiment of FIG.

FIG. 6 is a perspective view of the photoelectric conversion device of the present invention.
As shown in the figure, signal charges generated by infrared rays detected by the superlattice structure are accumulated in the gaps between the island-like superlattice structures 12 on the surface of the light transmitting substrate 11 on which the superlattice structure 12 is formed. A plurality of signal charge storage sections 26 such as capacitors formed by a storage gate electrode 23, an insulating film 24, and a potential well 25 of a light transmitting substrate for transferring the signal charges stored in the signal charge storage sections 26. Transfer gate electrode 27
Are connected to a line selection circuit such as a MOS switching array (not shown) for reading out the signal charges, and a switching circuit for switching the lines is provided adjacent to the signal charge storage section.

Further, a bias voltage is applied to a bias electrode 29 through a high-resistance layer 28 formed on the top of the superlattice structure 12.
The structure extends over the ground electrode 36 formed at the bottom of the superlattice structure 12. Infrared rays enter the superlattice structure 12,
When the resistance of the superlattice structure 12 decreases, the resistance changes so as to approach the potential of the individual electrode 33. The potential of the input gate electrode 38 connected to the individual electrode 33 also changes, and the potential well under the storage gate electrode 23 from the source diode (n ⁺ ) 42
Many free electrons flow into 25.

That is, the signal charges are stored in the signal charge storage section 26. The stored signal charges are transferred to the transfer gate electrode.
When a voltage is applied to 27, the data is read from the drain diode (n ⁺ ) 43 through the In bump 34. Since signal accumulation and line addressing can be performed on the light transmitting substrate side having the superlattice structure, the signal processing chip to be face-bonded can be, in extreme cases, only wiring, and can be thermally expanded with the light transmitting substrate 11. Advantages such as the use of a suitable material are obtained.

As another embodiment, as shown in FIG.
A sensing element chip in which a signal reading electrode 44 connected to a plurality of drain diodes in a direction perpendicular to the bias electrode 29 and the transfer gate electrode 27 is formed, and the light transmission substrate 11 on which the superlattice structure is formed is cut to a predetermined size. Although not shown, a good monolithic line address type photoelectric conversion device can be formed by disposing a line selection circuit, a multiplexer circuit, and the like.

In order to produce a photoelectric conversion device having sensitivity to infrared rays of, for example, 8.3 μm to 10 μm, as shown in FIG. A doped GaAs layer 51 is provided, the thickness of GaAs forming the quantum well layer 31 of the superlattice structure is set to 40 °, and the thickness of the Ga _1-x Al _x As layer forming the barrier layer 32 of the superlattice structure is formed. In order to change the height of the barrier layer 32 to 300 mm, the thickness of the Ga _1-x Al _x
As shown in FIG. 8 (b), the Ga _1-x Al _x As layer is preferably formed so that the x value is gradually reduced as the As layer extends from the top surface to the bottom surface.

In this way, as shown in FIG. 8 (c), the height of the barrier layer is gradually reduced from the top surface to the bottom surface of the superlattice structure, and long-wavelength infrared rays can be detected. Further, in this case, as shown in FIG. 9, a high-sensitivity spectral sensitivity characteristic curve in which spectral sensitivity does not decrease over a wide range of wavelengths.
A photoelectric conversion device having 41 is obtained. As described above, according to the photoelectric conversion device of the present invention, one side of the peripheral end surface of the superlattice structure formed in the shape of an island on the light transmitting substrate is 45 degrees with respect to the superlattice plane of the superlattice structure. By making the inclined surface having the angle of 反射 as the reflective surface, the infrared light incident from the light transmitting substrate side enters the superlattice structure almost parallel to the superlattice surface, and the incident infrared light is efficiently The converted photoelectric conversion device with improved sensitivity is obtained.

The sensing element surface on which a plurality of superlattice structures are arranged can be formed as a surface perpendicular to the optical axis of the incident infrared light, so that there is an advantage that a normal optical system can be used. Further, according to the present invention, an opaque film or a non-reflective film is formed on the end surface facing the reflection surface, and the surface of the superlattice structure portion facing the light transmission substrate and the island-like surface where the light transmission substrate is exposed are formed. An anti-reflection film is also formed in the gap of the superlattice structure, so that infrared light not absorbed by the superlattice structure enters the adjacent superlattice structure or enters other than the superlattice structure. Infrared rays
In order to prevent stray light from being reflected by the Si signal processing chip or the like, the image quality of the infrared image and the resolution of the image quality are improved.

According to the present invention, a light transmitting plate having a plurality of convex portions on its surface is arranged in parallel with the light transmitting substrate on the side opposite to the surface on which the island-shaped superlattice structure is formed. A plurality of convex portions are formed on the surface of the light transmitting substrate opposite to the surface on which the superlattice structure is formed, and the incident infrared light is focused on a minute portion, so that the incident infrared light can be efficiently superposed. This has the effect that it can be introduced into the grating structure, and the light receiving sections sparsely arranged in the focal plane can function as if they occupy most of the focal plane. A state equivalent to almost no area can be obtained.

Further, since the superlattice structure can be made smaller, the dark current when a constant bias voltage is applied can be reduced substantially in inverse proportion to the area of the superlattice structure, and the performance of the photoelectric conversion device can be reduced. Improvement can be achieved. According to the present invention,
Since the superlattice structure may be small, multiple large-area signal charge accumulators are formed in the gaps between the expanded superlattice structures to store a large amount of signal charges generated by infrared rays detected by the superlattice structure It is possible to increase the sensitivity of the photoelectric conversion device.

Further, a switching circuit for line switching can be provided, so that the structure on the signal processing chip side and the entire structure of the photoelectric conversion device can be greatly simplified, and the reliability and cost of the photoelectric conversion device can be improved. Further, according to the present invention, by continuously changing the thickness of the quantum well layer, the barrier height and the thickness of the barrier layer, the detection wavelength range is expanded, and the incident infrared light can be effectively photoelectrically converted. Become like

[0038]

As described above, according to the present invention, there is an effect that a photoelectric conversion device having a superlattice structure having high sensitivity, low cost and high resolution can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the apparatus of the present invention.

FIG. 2 is a second embodiment of the apparatus of the present invention.

FIG. 3 is an explanatory diagram of a structure of an antireflection film of the present invention.

4A and 4B are explanatory views of a light incident portion of the device of the present invention, wherein FIG. 4A is a structure having a transparent plate and FIG. 4B is a structural diagram without a transparent plate.

FIG. 5 is an explanatory view of another light incident portion of the device of the present invention.

FIG. 6 is a perspective view of the photoelectric conversion device of the present invention.

FIG. 7 is another perspective view of the photoelectric conversion device of the present invention.

8A and 8B are explanatory views of a superlattice structure of the present invention, wherein FIG. 8A is a plan view of the superlattice structure, FIG. 8B is a diagram showing the relationship between the x value and the position of the Ga _1-x Al _x As layer, (c) is a distribution diagram of the height of the barrier layer of the Ga _1-x Al _x As crystal layer.

FIG. 9 is a spectral sensitivity characteristic diagram of the apparatus of the present invention.

FIG. 10 is an explanatory diagram of a conventional device.

FIG. 11 is a spectral sensitivity characteristic diagram of a conventional device.

[Explanation of symbols]

 11 Light transmitting substrate 12 Super lattice structure 13 Reflecting surface 14 Super lattice surface 16 Opaque film 17 Conductive translucent thin film layer 18 Transparent layer 19 Reflecting layer 21 Convex part 22 Light transmitting plate 23 Storage gate electrode 24 Insulating film 25 Potential well 26 Signal charge storage section 27 Transfer gate electrode 28 High resistance layer 29 Bias electrode 31 Quantum well layer 32 Barrier layer 33 Individual electrode 34 Bump 35 Non-reflective film 36 Ground electrode 38 Input gate electrode 41 Spectral sensitivity characteristic curve 42 Source diode 43 Drain diode 44 Signal readout electrode 51 Highly doped GaAs layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01L 27/14-27/148 H01L 31/09-31/101

Claims (9)

(57) [Claims] A superlattice structure (12) in which thin layers of different semiconductors are alternately deposited a plurality of times, wherein the superlattice structure (12) detects infrared rays. A superlattice structure (1) is placed on a light transmitting substrate (11) through which infrared
2) is formed in the shape of an island, and at least one end face of the peripheral end face of the superlattice structure portion (12) having an island shape is more than 30 degrees with respect to the superlattice surface (14) of the superlattice structure portion (12). A photoelectric conversion device characterized by an inclined surface having an angle of up to a degree, the inclined surface being a reflecting surface (13) for reflecting infrared light incident from the light transmitting substrate (11) side. 2. Among the peripheral end faces of the island-shaped superlattice structure portion (12), an end surface facing the reflection surface (13) is opaque so that infrared light propagated from the superlattice structure portion (12) side is not transmitted. Membrane (1
6. The photoelectric conversion device according to claim 1, further comprising a non-reflection film (35) that does not transmit and does not reflect infrared light transmitted from the superlattice structure (12). 3. The surface of the island-shaped superlattice structure (12) facing the light transmitting substrate (11), and the island-shaped superlattice structure (12) where the light transmitting substrate (11) is exposed. 3. An anti-reflection film (35), which does not transmit infrared light and hardly reflects light, is provided on at least one of the gaps between the two.
The photoelectric conversion device as described in the above. 4. The transparent anti-reflection film (35), a conductive semi-transparent thin film layer (17), and a transparent layer made of a dielectric when viewed from the light transmitting substrate (11) side.
(18), formed by three layers of a metal reflective layer (19),
The conductive translucent thin film layer (17), an individual electrode (33) for detecting infrared rays in the superlattice structure (12), or a ground electrode (36)
4. The photoelectric conversion device according to claim 3, wherein the photoelectric conversion device is used as a part of or both of the electrodes. 5. A light having a plurality of projections (21) on the surface opposite to the surface on which the island-shaped superlattice structure (12) is formed so as to be parallel to the light transmitting substrate (11). 5. The photoelectric conversion device according to claim 1, wherein a transmission plate is provided. 6. A plurality of projections (21) are formed on the surface of the light transmitting substrate (11) opposite to the surface on which the island-like superlattice structure (12) is formed.
5. The method of claim 1, 2, 3 or 4, wherein
The photoelectric conversion device as described in the above. 7. The photoelectric conversion device according to claim 5, wherein the plurality of projections have a wavy shape in a semi-cylindrical shape. 8. The superlattice structure section (12) is provided in the gap of the island-shaped superlattice structure section (12) on the surface of the light transmitting substrate (11) on the side where the island-shaped superlattice structure section (12) is formed. A signal charge storage section (2) for storing signal charges generated by infrared rays detected in (12).
8. The photoelectric conversion device according to claim 5, further comprising a switching circuit for line switching for sequentially reading out the signal charges in the signal charge storage section. 9. The quantum well layer (31) of the superlattice structure (12)
3. The wavelength range of infrared light that can be detected is expanded by continuously changing the thickness and the barrier height and thickness of the barrier layer (32) during the formation of the superlattice. 3,
The photoelectric conversion device according to 4, 5, 6, 7, or 8.