JPH05136445A - Photoelectric device and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the deviation of connection electrodes by forming a conductor film, an insulating film, a cadmium-containing compound semiconductor film, a mercury-containing compound semiconductor film, and a photodetector element composed of a p-n junction in sequence, and then forming a metal film as the connection electrode and aperture. CONSTITUTION:A conductor film 11, an insulating film 12, a cadmium-containing compound semiconductor film 13, and a mercury-containing compound semiconductor film 14 are laminated into a predetermined pattern over a signal processing element 4 on a semiconductor substrate 5. A photodetector element 3 is formed of a p-n junction in the compound semiconductor film 14, and its sides and light input part are surrounded by a metal film with insulating films 15A and 15B in between. The metal film serves both as a connection electrode 17 between the signal input of the signal processing element 4 and a substrate electrode 19 and as the aperture 18 of the photodetector element 3. In this structure, the deviation of electrodes due to the change in temperature is prevented, and thus the device is easy to manufacture.

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 in which semiconductor elements are formed on different semiconductor substrates having different coefficients of thermal expansion and the semiconductor elements are connected to each other.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a compound semiconductor substrate 1 having a high sensitivity to infrared rays, for example, P-type mercury cadmium tellurium (Hg _1-x Cd _x Te), is used. By providing the N ⁺ layer 2 by ion-implanting impurity atoms of a conductive type, the light detecting element 3 formed of a photovoltaic type infrared detecting element is formed.

On the other hand, the charge-coupled device for signal-processing the detection signal obtained by the light-sensing device 3 and the signal-processing device 4 such as an input diode which serves as a signal input portion of the charge-coupled device are provided with the above compound. For example, a P type silicon (Si) substrate 5 having a smaller coefficient of thermal expansion than the semiconductor substrate 1 is formed, and the signal processing element 4 and the photodetecting element 3 are coupled using a metal bump 6 to form a hybrid type photoelectric conversion element. It forms the converter.

[0004]

By the way, the above photoelectric conversion device is required to have higher sensitivity and higher resolution. Therefore, the element area (light receiving area) of the photodetecting element 3 is increased and the compound semiconductor substrate 1 is also required. Photo-sensing element 3 per unit area of
It is also necessary to increase the quantity of.

On the other hand, the thermal expansion coefficient of Hg _1-x Cd _x Te substrate 1 is 5
At a temperature of × 10 ^-6 ° C ^-1 , the coefficient of thermal expansion of the Si substrate 5 is higher than 3.5 × 10 ^-6 ° C ^-1 . This photoelectric conversion device is used by cooling it to a low liquid nitrogen temperature of 77 ° K during operation to prevent the effect of thermal noise, and is installed in a room temperature environment when not operating. Will be exposed to temperature fluctuations from low temperature to room temperature.

Therefore, Hg _1-x Cd _x Te substrate 1 and Si
The substrate 5 is subject to thermal strain due to temperature fluctuations, and the thermal expansion coefficients of the two substrates 1 and 5 are different.
Naturally, the amount of thermal strain on 5 is different. Then, the stress due to the difference in the thermal strain amount between the two is applied to the metal bump 6 that bump-bonds the photodetection element 3 and the signal processing element 4, and the metal bump 6 is cracked, or the substrates of the both are formed. Metal bump 6 is displaced from 1,5 and both elements 3,4
This causes a problem of poor connection between the two.

Such a problem is more likely to occur because the capacitance of the compound semiconductor substrate increases as the sensitivity of the photodetector increases. The present invention solves the above-mentioned problems, the connection electrodes connecting elements formed on semiconductor substrates having different thermal expansion coefficients do not shift in position, and the aperture for defining incident light of the photo-detecting element is a subsequent step. It is an object of the present invention to provide a photoelectric conversion device that does not need to be separately formed in the above step and is formed in the same step as a connection electrode that connects the photodetection element and the signal processing element, and a method for manufacturing the device.

[0008]

According to a first aspect of the present invention, a photoelectric conversion device includes a conductive film, an insulating film, a compound semiconductor film containing cadmium, and mercury on a signal processing element provided on a semiconductor substrate. A compound semiconductor film is provided as a laminated film in a predetermined pattern, a photodetector with a PN junction is provided on the compound semiconductor film containing mercury, and the side surface of the photodetector formed in the laminated film and the light of the photodetector A metal film is provided around the incident part with an insulating film interposed therebetween, and the metal film is used as a connection electrode for connecting the signal input part of the signal processing element and a substrate electrode, and an aperture of the photodetection element. ..

Further, according to a second aspect of the present invention, there is provided a method for manufacturing a photoelectric conversion device including a conductive film, an insulating film, a compound semiconductor film containing cadmium, and mercury on a signal processing element provided on a semiconductor substrate. A compound semiconductor film is sequentially formed as a laminated film in a predetermined pattern, and an impurity atom of a reverse conductivity type is ion-implanted into the compound semiconductor film containing mercury to form a PN junction, thereby forming a photodetector element. An insulating film is selectively formed around a region of the compound semiconductor film containing mercury excluding the light incident part and around the laminated film of the compound semiconductor films, and the extraction electrode of the photodetection element is formed on the insulating film. Along with that, forming an insulating film on which the light incident portion is opened, on the insulating film, connected to the extraction electrode, and formed on the side surface of the photodetection element formed in the laminated film, Signal of the signal processing element A connection electrode connecting the force and the substrate electrode is formed around the light incident portion of the light sensing element, and forming a metal film comprising an aperture of the light sensing element.

[0010]

The apparatus of the present invention, as shown in FIGS. 1 and 2 as the embodiments of claims 1 and 2, selectively and predeterminedly arranges on the Si substrate 5 having the signal processing element 4 formed thereon. The conductive film 11 having a pattern, the CdTe film 13, and the Hg _1-x Cd _x Te film 14 are laminated and formed, and a PN junction is formed on the Hg _1-x Cd _x Te film 14 to form the photodetector element 3.

Then, through the insulating films 15A and 15B, it becomes an aperture 18 for restricting the incident light of the photo-detecting element 3 and is connected to the working electrode (conductive film 11) of the photo-detecting element 3 and the substrate electrode 19. The connection electrode 17 is provided separately for each of the individual photo-sensing elements 3 formed of the Hg _1-x Cd _x Te film 14.

In this way, the light detecting element 3 is
Since it is formed on the compound semiconductor substrate 1,
Hg selectively deposited on the signal processing element 4_1-x
Cd_xSince it is formed on the Te film 14, Hg_1-xCd_xTe and Si
Even if the coefficient of thermal expansion is different, this Hg _1-xCd_xThe capacity of Te film 14
Because it is small, it is less affected by thermal strain and can be connected
The electrode 17 does not cause a phenomenon such as displacement.

Further, the light detecting element 3 and the working electrode (conductive film 11)
, The In film that connects the substrate electrode 19 and the I that will become the aperture 18.
Since the n film is formed in the same process, it is not necessary to separately form the aperture 18 in a later process, and the manufacturing process is simplified.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings. In the photoelectric conversion device of the present invention, as shown in FIG. 1, an N ⁺ layer 2 is formed on a P-type Si substrate 5, and a signal processing element 4 serving as an input diode of a charge-coupled element is formed.
This inputs the detection signal obtained by the light detection element 3.

A conductive film 11 which is a compound film of Al and Si is formed on the signal processing element 4 by a sputtering method or the like. On top of that, an insulating film 12 made of aluminum oxide (Al ₂ O ₃ ) is deposited, high-frequency sputtering method, anodizing method (Al is sputtered on the substrate, and the Al serving as the substrate and the anode is used as an anodizing solution. Method of dipping Al ₂ O ₃ ) to form a CdTe film 13 and P-type Hg _1-x Cd _x Te.
The film 14 is formed by lamination using a molecular beam epitaxial method or a metal organic chemical vapor deposition method (MOCVD method).

Then, a ZnS film 15A having an opening at the center is formed on the Hg _1-x Cd _x Te film 14 by vapor deposition or a high frequency sputtering method. The ZnS film 15A is used as a mask for the P-type film. Boron atoms, which become N-type impurity atoms, are selectively ion-implanted into the Hg _1-x Cd _x Te film 14 to form an N ⁺ layer 2 for forming the photodetector element 3.

Then, on the ZnS film 15A, N⁺Layer 2
And Al for connecting the substrate electrode 19 and the conductive film 11
The extraction electrode 16 is formed. This CdTe film 13 and Hg_1-x
Cd_xThe Te film 14 is formed on the side surface of the photodetector element 3 formed in the laminated film.
Is the extraction electrode 16 and the substrate electrode 19, and the extraction electrode
Connection electrode 17 made of In for connecting 16 and the conductive film 11
Are formed. On this connection electrode 17, N ⁺Layer 2
A ZnS film 15B with an opening is formed on top of it, and N
⁺An aperture 18 made of In is formed so as to surround the layer 2.
Has been done. This aperture 18 is the same as the connection electrode 17
Vapor deposition in the process of, and lift-off using a photoresist film.
It is formed by the F method.

A method of manufacturing such a photoelectric conversion device of the present invention will be described. As shown in FIG. 2A, the signal processing element 4 of the input diode of the charge-coupled device formed on the P-type Si substrate 5 is ion-implanted with N-type impurity atoms into the substrate. Is formed.

A SiO ₂ film 21 is formed on the substrate 5 as a surface protective film, and the SiO ₂ film on the signal processing element 4 is formed.
A predetermined region of 21 is opened to form a conductive film 11 of a compound of Al and Si. In addition, the SiO ₂ film 21 on the substrate electrode 19 serving as the ground electrode
To expose the substrate electrode 19.

Then, as shown in FIG. 2B, an Al ₂ O ₃ film is selectively formed on the conductive film 11 by using a photoresist film as a mask and selectively using a sputtering method, a CVD method, an anodization method or the like. The insulating film 12 is formed to a thickness of about 1 μm.

Then, as shown in FIG. 2 (c), silicon nitride
Using the (Si ₃ N ₄ ) film as a mask, the CdTe film 13 is selectively formed on the insulating film 12 made of the Al ₂ O ₃ film by a molecular beam epitaxial method or a metal organic chemical vapor deposition method (MOCVD method). Form to a thickness of 10 μm.

Then, as shown in FIG. 2 (d), silicon nitride
Using the (Si ₃ N ₄ ) film as a mask, a P-type Hg _1-x Cd _x Te film 14 is selectively formed on the CdTe film 13 to a thickness of about 1.5 μm by a molecular beam epitaxial method, a MOCVD method, or It is formed using a liquid phase epitaxial growth method.

Then, as shown in FIG. 3 (a), a CdTe film is formed by a vapor deposition method in which the photoresist film is used as a mask and the substrate is placed in an oblique direction with respect to a ZnS vapor deposition source, or by a high frequency sputtering method or a CVD method. A ZnS film 15A is formed to a thickness of about 0.4 μm on the side surface and the surface of the laminated film of 13 and the Hg _1-x Cd _x Te film 14.

Then, an opening is formed on the ZnS film 15A,
Boron atoms are ion-implanted using the ZnS film 15A as a mask to form the N ⁺ layer 2, and a PN junction is formed in the Hg _1-x Cd _x Te film 14 to form the photodetector 3 shown in FIG. 3 (b). To form.

Next, as shown in FIG. 3 (b), the ZnS film 15A
To connect the N ⁺ layer 2 and the conductive film 11 on top, and N ⁺
An In extraction electrode 16 for connecting the Hg _1-x Cd _x Te layer 14 other than the layer 2 and the substrate electrode 19 is formed by vapor deposition.

Next, as shown in FIG. 3 (c), a ZnS film 15B is formed on the extraction electrode 16 by vapor deposition on the aperture formation region in a later step, selectively using a photoresist film as a mask.

Then, as shown in FIG. 3 (d), the CdTe film 13 is formed.
And the Hg _1-x Cd _x Te film 14 on the side surface of the laminated film, the extraction electrode
A ZnS film surrounding the N ⁺ region 2 and a connection electrode 17 for connecting the 16 and the conductive film 11 and for connecting the extraction electrode 16 and the substrate electrode 19.
An In film to be the In aperture 18 is vapor-deposited on the 15B to a thickness of about 25 μm, and is simultaneously formed by a lift-off method using a photoresist film.

In this lift-off method, a photoresist film (not shown) is formed on a region other than the formation region of the aperture 18 and the formation region of the connection electrode 17, In is formed on the Si substrate 5, and then the photoresist film is formed. Is removed with a resist film remover to form an In film at a desired location.

In this way, unlike the conventional photo-sensing element, the photo-sensing element of the present invention is not formed on the compound semiconductor substrate but is selectively deposited on the input diode of the signal processing element. Since the Hg _1-x Cd _x Te film is formed, even if the thermal expansion coefficients of Hg _1-x Cd _x Te and Si are different, the capacity of this Hg _1-x Cd _x Te film is small, so the thermal strain Less affected by.

Further, a photodetector and a conductive film provided on the Si substrate,
In addition, since the aperture of the In film around the N ⁺ layer of the photodetector is formed at the same time when the In film connecting the photodetector and the substrate electrode is formed, it is not necessary to separately provide the aperture in a later step, A high-resolution photoelectric conversion device can be obtained by a simple manufacturing process.

[0031]

As described above, according to the present invention, it is possible to prevent the connection electrodes from being displaced due to temperature fluctuations at high resolution when operating and when not operating. Further, since the apertures for each of the photo-detecting elements can be formed at the same time in the step of forming the connection electrode, there is an effect that the manufacturing process becomes easy.

[Brief description of drawings]

FIG. 1 is a perspective view and a cross-sectional view of a photoelectric conversion device of the present invention.

FIG. 2 is a cross-sectional view showing the method of manufacturing the device of the present invention.

FIG. 3 is a cross-sectional view showing the method of manufacturing the device of the present invention.

FIG. 4 is a cross-sectional view of a conventional photoelectric conversion device.

[Explanation of symbols]

2 N ⁺ layer 4 Signal processing element 5 Si substrate 11 Conductive film 12 Insulating film 13 CdTe film 14 Hg _1-x Cd _x Te film 15A, 15B ZnS film 16 Extraction electrode 17 Connection electrode 18 Aperture 19 Substrate electrode 21 SiO ₂ film

Front page continuation (72) Inventor Yamada Racing 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (2)

[Claims] 1. A signal processing element provided on a semiconductor substrate (5).
(4) A conductive film (11), an insulating film (12), a cadmium-containing compound semiconductor film (13), and a mercury-containing compound semiconductor film (14) are provided as a laminated film in a predetermined pattern and contain the mercury. The compound semiconductor film (14) is provided with a light detecting element (3) having a PN junction, and the side surface of the light detecting element (3) formed on the laminated film and the periphery of the light incident portion of the light detecting element (3). A metal film is provided by separating the insulating films (15A, 15B), and the metal film connects the signal input part of the signal processing element (4) to the substrate electrode (19), and the photodetection element. A photoelectric conversion device having the aperture (18) of (3). 2. A signal processing element provided on a semiconductor substrate (5)
(4) A conductive film (11), an insulating film (12), a compound semiconductor film (13) containing cadmium, and a compound semiconductor film (14) containing mercury are sequentially formed as a laminated film in a predetermined pattern on the mercury film. A photodetector element (3) is formed by ion-implanting a reverse-conductivity-type impurity atom into the compound semiconductor film (14) containing mercury to form a photodetector (3). An insulating film (15A) is selectively formed around the laminated film of the compound semiconductor film (13, 14) except the light incident part, and the photodetector element (3A) is formed on the insulating film (15A). ) Extraction electrode (1
6) is formed, and an insulating film (15B) in which the light incident part is opened is formed thereon, and the insulating film (15A, 15B) is connected to the extraction electrode (16), and A connection electrode (17), which is formed on the side surface of the light detection element (3) formed in the laminated film and connects the signal input part of the signal processing element (4) to the substrate electrode (19), and the light detection element (3 )
2. A method for manufacturing a photoelectric conversion device, comprising forming a metal film which is formed around the light incident part of and which serves as an aperture (18) of the light detecting element (3).