JPH09270527A - Semiconductor photodetector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the lattice mismatch to obtain a high photodetection sensitivity and low dark current characteristic by forming a deformation InGaAs photoabsorption layer between an InGaAs photoabsorption layer and InP substrate. SOLUTION: A deformation In GaAs photoabsorption layer 3 is formed between an InGaAs photoabsorption layer 4 and InP substrate 1. P-type InP regions 9 are partly formed in an InP window layer 7 and/or InP multiplication layer 6. When e.g. a light of 1.65μm wavelength is incident on such avalanche photodiode having the two InGaAs photoabsorption layers 3 and 4, it goes from the window layer 7 into the region 9, passes through the multiplying, intermediate and photoabsorption layers 6, 5, 4 to the absorption layer 3 to absorb it. When e.g. a light of 1.55 or 1.3μm in wavelength is incident, it goes from the window layer 7 into the region 9, passes through the multiplying and intermediate and photoabsorption layers 6, 5 to the absorption layer 4 to absorb it. Hence the light of 1.65μm in wavelength is absorbed at a high efficiency. Thus it is possible to suppress the lattice mismatch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light receiving element, and more particularly to a semiconductor light receiving element suitable for use in optical measurement and optical communication.

[0002]

2. Description of the Related Art A conventional semiconductor light receiving element of this type is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 4-92479 and 5-28373.
No. 0, JP-A-62-296481 and the like are proposed.

Optical fibers are currently used as routes for optical communication. The OTDR (Optical Time) is used as a maintenance management method for an optical fiber network laid as an optical communication line.
Domain Reflectometer). The OTDR is a device for investigating the breaking point of the installed optical fiber, and its basic principle is to monitor the Rayleigh scattered light generated when the pulsed light injected into the fiber propagates in the fiber, If there is a breaking point inside, Rayleigh scattered light will not return. Therefore, the position of the break point can be accurately known by converting the time until the Rayleigh scattered light disappears into a distance. However, in this case, there is a problem that the communication line must be connected to the OTDR device, and thus the communication line is temporarily cut off.

In order to solve this problem, therefore, light in the wavelength range of 1.65 μm, which is different from the transmission wavelength of 1.3 μm or 1.5 μm in optical communication, is used, and the line is monitored at the same time while using the communication line. A method of doing it all the time is being considered.

FIG. 4 shows a conventional example of a light receiving element having sensitivity to a wavelength of 1.65 μm. FIG. 4 shows the above-mentioned Japanese Patent Laid-Open No.
FIG. 3 is a diagram showing a configuration of a light receiving element proposed in Japanese Patent Laid-Open No. 283730/1983, in which a strained lattice layer 5 is used as a lattice mismatch relaxation layer 44.
4 and the strained superlattice layer 55 are combined to improve the dark current characteristic in the light receiving element in which the light absorption layer 45 which is not lattice-matched to the substrate material is provided on the substrate via the lattice mismatch relaxation layer 44. .

That is, referring to FIG. 4, this light receiving element comprises an InP substrate 1, an InP buffer layer 2, and a GaInA layer.
s buffer layer 26, strained lattice layer 24, InP / GaInA
The s strained superlattice layer 25 is sequentially epitaxially grown, the GaInAs light absorption layer 4 is grown thereon, and the InP cap layer 7 is sequentially grown. In the case of this light receiving element, by using strained GaInAs for the light absorption layer 4,
It can have sensitivity to light of 1.65 μm. However, since the element itself does not have a carrier amplification function, it is not suitable for use in an OTDR that detects weak scattered light.

A second conventional example of this type of light receiving element is shown in FIG. Referring to FIG. 5, n ⁺ -I on n ⁺ -InP substrate 1
After growing the nP buffer layer 2, n having a thickness of 1.5 to 2 μm is formed.
^--INAS / GaAs superlattice light absorbing layer 27, a thickness of 0.
Mesa etching was performed on a crystal in which a 1 μm-thickness n ⁻ -InGaAsP layer 5, a 1.5 μm-thick n ⁺ -InP multiplication layer 6 and a 1 μm-thick p-InP layer 9 were sequentially grown.
A light receiving element is formed by depositing TiPtAu as the p-side electrode 12 and AuGeNi as the n-side electrode 14. As described above, the light absorption layer 27 has a superlattice layer structure of InAs and GaAs, so that the wavelength at the absorption edge can be increased to 3.2 μm.

However, the problem here is that the second
In the case of the conventional example, due to the formation of a superlattice of InAs and GaAs on InP, a lattice mismatch occurs at the interface, and a dark current occurs due to the lattice defect. The dark current causes noise, which lowers the sensitivity.

[0009]

As described above, the above-mentioned prior art has the following problems.

In the first prior art described with reference to FIG. 4, the OT which has low sensitivity and detects weak scattered light.
It has a problem that it is not suitable for use in DR.

The reason is that the element itself does not have a carrier amplifying function.

The second prior art APD (avalanche photodiode) described with reference to FIG.
In the above, there is a problem that a dark current is generated due to a lattice defect and noise is generated by the dark current, so that the sensitivity is lowered.

The reason is that InAs and GaA are formed on InP.
This is because a lattice mismatch occurs at the interface due to the formation of the superlattice of s, and a dark current is generated due to the lattice defect.

Therefore, the present invention solves the above-mentioned problems of the prior art, and is suitable for light having a wavelength of 1.65 μm, which is suitable for use as a light receiving element for line monitoring of an optical communication fiber network, for example. It is an object of the present invention to provide a semiconductor light receiving element capable of obtaining quantum efficiency, low dark current, and high current multiplication factor.

[0015]

To achieve the above object, the present invention provides a first conductivity type InP substrate, a first conductivity type strained InGaAs layer, a first conductivity type InGaAs layer, and a first conductivity type. A heteroepitaxial layer structure in which an InP multiplication layer and a first-conductivity-type InP window layer are sequentially formed is provided, and a second epitaxial layer is partially formed in the window layer and / or the multiplication layer.
A conductive InP region is provided, and the second InP region is further provided.
There is provided a semiconductor light receiving element comprising a second conductivity type electrode provided on a conductivity type InP region and a first conductivity type electrode provided on the first conductivity type InP substrate.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First, referring to FIG. 1, according to the embodiment of the present invention, a strained InGaAs layer of the first conductivity type (absorption edge wavelength λ = 1) is formed on an n ⁺ -(first conductivity type) InP substrate 1. .85μ
m) 3 and the first conductivity type InGaAs layer (absorption edge wavelength λ =
1.65 μm) 4, a first-conductivity-type InP multiplication layer 6, and a first-conductivity-type InP window layer 7 are sequentially formed, and the heteroepitaxial layer structure is provided in the window layer 7 and / or the multiplication layer. 6
A p- (second conductivity type) InP region 9 is partially provided therein, and a p-side (second conductivity type) electrode 12 provided on the second conductivity type InP region 9 provided in the window layer 7; An n-side (first conductivity type) electrode 14 provided on the first conductivity type InP substrate 1 is provided.

The principle of the embodiment of the present invention will be described below. In an APD (avalanche photodiode) having two light absorption layers of strained InGaAs and InGaAs, 1.
When 65 μm light is incident, the light is incident from the window layer 7 side into the p ⁺ diffusion region 9, and the multiplication layer 6, the intermediate layer 5, and the InGaA
After passing through the s light absorption layer 4, it is absorbed by the strained n-InGaAs light absorption layer 3. The carriers generated by the light absorbed here are accelerated by the electric field applied between the p-side electrode 12 and the n-electrode 14, flow into the p-side electrode 12, and are discharged to an external circuit to become a photocurrent.

On the other hand, when a light of 1.55 μm or 1.3 μm is incident, the light is incident on the p ⁺ diffusion region 9 from the window layer 7 side, passes through the multiplication layer 6 and the intermediate layer 5, and then InGaA.
It is absorbed by the light absorption layer 4. The carriers generated by the light absorbed here are the p-side electrode 12 and the n-electrode 14
It is accelerated by an electric field applied between them, flows into the p-side electrode 12, and is discharged to an external circuit to become a photocurrent.

That is, the light of 1.55 / 1.3 μm is absorbed by the light absorption layer 4 on the upper layer side, and the light of 1.65 μm is absorbed by the strained light absorption layer 3 on the lower layer, and then photoelectrically converted. .

With such a structure, as will be described later, it is possible to absorb light of 1.65 μm with a high efficiency of 0.85 A / W or more, for example.

Further, distortion ⁿ between the InGaAs light absorbing layer 4 and the InP substrate 1 - By sandwiching the -InGaAs light-absorbing layer 3, it is possible to suppress the lattice mismatch, 20 nA
The following low dark current characteristics can be obtained. Furthermore, strain n-In
The carriers generated by the light absorption in the GaAs light absorption layer 3 or the InGaAs light absorption layer 4 cause avalanche multiplication by the electric field applied to the n ⁺ -InP multiplication layer 6, so that the carriers are high, for example, 30 times or more. Gain is obtained.

[0023]

EXAMPLES Examples of the present invention will be described below with reference to the drawings in order to describe the above-described embodiments of the present invention in more detail.

FIG. 1 is a sectional view schematically showing the structure of an embodiment of a semiconductor light receiving element according to the present invention.

Referring to FIG. 1, a carrier concentration of 10 ¹⁵ is preferably formed on the n ⁺ -InP substrate 1 by a vapor phase growth method.
N-In having a thickness of 2 × 10 ¹⁶ cm ⁻³ and a layer thickness of 1 to ³ μm
In order to absorb light of 1.65 μm, the P buffer layer 2 preferably has an absorption edge wavelength λ = 1.85 μm and a carrier concentration of 10
Strained n-InG having a thickness of ^{15 to} 2 × 10 ¹⁶ cm ^-3 and a layer thickness of 1 to ³ μm
aAs light absorption layer 3 and 1.55 μm or 1.3 μm
As the n ⁻ -InGaAs light absorption layer for absorbing the light of, the carrier concentration is preferably 10 ^{15 to} 5 × 10 ¹⁵ c
m ⁻³ , n ⁻ -InGaAs light absorption layer 4 having a layer thickness of ^{3 to} 4 μm
After growing, the carrier concentration is preferably 3 × 10 ¹⁵ to
10 ¹⁶ cm ⁻³ , n-InG having a layer thickness of 0.03 to 0.5 μm
An aAsP intermediate layer 5 is grown, and then, as a multiplication layer layer,
Preferably, the n ⁺ -InP multiplication layer 6 having a carrier concentration of 10 ¹⁶ to 4 × 10 ¹⁶ cm ^-3 and a layer thickness of 0.5 to ³ μm is grown.
Finally, the window layer preferably has a carrier concentration of 2 × 10 ^15.
The n ⁻ -InP window layer 7 having a layer thickness of 6 × 10 ¹⁵ cm ^{−3 and a} layer thickness of 1 to 2 μm is grown.

In the present embodiment, as an example, n ⁺ -InP
The n-InP buffer layer 2 described above is formed on the substrate 1 by vapor phase growth so that the carrier concentration is 10 ¹⁵ cm ⁻³ and the layer thickness is 2 μm.
m, the strained n-InGaAs light absorption layer 3 has a carrier concentration of 10 ¹⁵ cm ^-3 and a layer thickness of 2 μm, and the n ⁻ -InGaAs light absorption layer 4 has a carrier concentration of 3 × 10 ¹⁵ cm ^-3 and a layer thickness of Four
The n-InGaAsP intermediate layer 5 is grown as
The carrier concentration is 10 ¹⁶ cm ⁻³ , the layer thickness is 0.5 μm,
The n ⁺ -InP multiplication layer 6 has a carrier concentration of 3 × 10 ¹⁶ c
m ⁻³ , the layer thickness is 1.4 μm, and the n ⁻ -InP window layer 7 is
It was grown with a carrier concentration of 5 × 10 ¹⁵ cm ⁻³ and a layer thickness of 1.4 μm.

A mask is grown on the surface of the epitaxial wafer thus grown by the CVD (Chemical Vapor Deposition) method, and the guard ring 8 is formed by the ion implantation method of Be, for example.

Next, a window of a diffusion mask is opened so as to overlap the guard ring 8 and the p ⁺ region 9 of 10 ¹⁷ to 10 ²⁰ cm ^-3 corresponding to the light receiving portion is selectively formed by sealing diffusion of Zn, for example. Form.

After that, the insulating film 11 is formed on the surface side by a usual method.
After the growth, a part of the insulating film 10 on the p ⁺ region 9 is perforated to form a p-side contact electrode 11 by, for example, a vapor deposition method, and then a heat treatment is performed. Then, the p-side electrode 12 is formed so as to cover the p-side contact electrode 11.

Subsequently, after the n-side contact electrode 13 is formed on the back surface of the n-InP substrate 1 by, for example, the vapor deposition method,
A heat treatment is performed, and finally, the n-side electrode 14 is formed so as to cover the n-side contact electrode 13.

Strained InGaAs manufactured in this way
FIG. 2 shows the spectral sensitivity characteristics of the APD having the two light absorption layers 3 and 4 of InGaAs and InGaAs (horizontal axis represents wavelength, vertical axis represents sensitivity).

When light of 1.65 μm is incident on the APD, the light is incident on the p ⁺ diffusion region 9 from the side of the InP window layer 7, transmitted through the multiplication layer 6 and the intermediate layer 5, and then InGaAs.
The light is absorbed by the light absorption layer 4 and the strained n-InGaAs light absorption layer 3. The carriers generated by the light absorbed here are accelerated by the electric field applied between the p-side electrode 12 and the n-electrode 14, flow into the p-side electrode 12, and are discharged to an external circuit to become a photocurrent.

On the other hand, when a light of 1.55 μm or 1.3 μm is incident, the light is incident on the p ⁺ diffusion region 9 from the window layer 7 side, transmitted through the multiplication layer 6 and the intermediate layer 5, and then InGaA.
It is absorbed by the light absorption layer 4. The carriers generated by the light absorbed here are the p-side electrode 12 and the n-electrode 14
It is accelerated by an electric field applied between them, flows into the p-side electrode 12, and is discharged to an external circuit to become a photocurrent.

That is, the light of 1.55 / 1.3 μm is absorbed by the upper light absorbing layer 4 and the light of 1.65 μm is absorbed by the lower strained light absorbing layer 3, and photoelectrically converted. .

By adopting such a structure, 1.6
Light of 5 μm can be absorbed with high efficiency of 0.85 A / W or more, and high-speed response is possible to light of 1.55 / 1.3 μm.

Further, between the InGaAs light absorbing layer 4 and the InP substrate 1, strain ⁿ - By sandwiching the -InGaAs light-absorbing layer 3, it is possible to suppress the lattice mismatch, 20n
A low dark current characteristic of A or less can be obtained.

Further, the strained n-InGaAs light absorption layer 3 or InGaAs is obtained by the effects of the above-described embodiment.
The carriers generated in the light absorption layer 4 cause avalanche multiplication by the electric field applied to the n ⁺ -InP multiplication layer 6, and a high multiplication factor of 30 times or more is obtained.

The above effects are obtained by the CVD method, the MOCVD (organic metal CVD) method, the MBE (molecular beam epitaxial growth) method, in addition to the epitaxial wafer by the vapor phase growth method.
The same effect can be obtained in an epitaxial wafer by the ALE (atomic layer epitaxial growth) method or the like.

A second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a sectional view showing the configuration of the second embodiment of the semiconductor light receiving element according to the present invention. In addition, in FIG. 3, the back surface of the substrate is illustrated as the upper side.

Referring to FIG. 3, on n ⁺ -InP substrate 1, the carrier concentration is preferably 10 by the vapor phase growth method.
^In order to absorb the n-InP buffer layer 2 having a thickness of ^{15 to} 2 × 10 ¹⁶ cm ⁻³ and a layer thickness of 1 to ³ μm and light of 1.65 μm, the absorption edge wavelength λ = 1.85 μm and the carrier concentration 10 are preferable.
Strained n-InG having a thickness of ^{15 to} 2 × 10 ¹⁶ cm ^-3 and a layer thickness of 1 to ³ μm
aAs light absorption layer 3 and 1.55 μm or 1.3 μm
As the n ⁻ -InGaAs light absorption layer for absorbing the light of, the carrier concentration is preferably 10 ^{15 to} 5 × 10 ¹⁵ c
m ⁻³ , n ⁻ -InGaAs light absorption layer 4 having a layer thickness of ^{3 to} 4 μm
After growing, the carrier concentration is preferably 3 × 10 ¹⁵ to
10 ¹⁶ cm ⁻³ , n-InG having a layer thickness of 0.03 to 0.5 μm
An aAsP intermediate layer 5 is grown, and then, as a multiplication layer layer, carrier concentration is preferably 10 ¹⁶ to 4 × 10 ¹⁶ c.
An n ⁺ -InP multiplication layer 6 having a thickness of m ⁻³ and a layer thickness of 0.5 to ³ μm is grown. Finally, the window layer is preferably an n ⁻ -InP window having a carrier concentration of 2 × 10 ^{15 to} 6 × 10 ¹⁵ cm ⁻³ and a layer thickness of 1 to 2 μm (this time, carrier concentration 5E15 cm ⁻³ layer thickness 1.4 μm). Grow layer 7.

In this embodiment, the n-InP buffer layer 2 has a carrier concentration of 10 ¹⁵ cm ^-3 , a layer thickness of 2 μm, and a strained n-InGa.
The As light absorption layer 3 has a carrier concentration of 10 ¹⁵ cm ⁻³ and a layer thickness of 2
μm, n ⁻ -InGaAs light absorption layer 4 has a carrier concentration of 3 × 10 ¹⁵ cm ⁻³ and a layer thickness of 4 μm, and the n-InGaAsP intermediate layer 5 has a carrier concentration of 10 ¹⁶ cm ⁻³ and a layer thickness of 0.5 μm.
The m, n ⁺ -InP multiplication layer 6 has a carrier concentration of 3 × 10 ¹⁶
cm ⁻³ , layer thickness 1.4 μm, and the n ⁻ -InP window layer 7 was grown at a carrier concentration of 5 × 10 ¹⁵ cm ⁻³ and layer thickness 1.4 μm.

A mask is grown by the CVD method on the surface of the epitaxial wafer thus grown, and the guard ring 8 is formed by, for example, the ion implantation method of Be.

Next, a window of a diffusion mask is opened so as to overlap the guard ring 8, and a p ⁺ region (p of 10 ¹⁷ to 10 ²⁰ cm ^-3 corresponding to a light receiving portion is formed by, for example, Zn diffusion and diffusion.
-InP) 9 is selectively formed.

After that, the insulating film 10 is formed on the front surface side by a usual method.
After growing, the insulating film 10 on the p ⁺ region 9 is perforated to form a p-side contact electrode 11 by, for example, a vapor deposition method, and then heat treatment is performed. A p-side electrode 12 is formed so as to cover the p-side contact electrode 11.

Subsequently, the back surface of the n-InP substrate 1 is chemically etched to form a radius of 120 μm to 150 μm.
A convex shape of about μm is formed to form a lens.

An antireflection film 15 (AR
Lens). N ⁺ -I to surround the lens
After forming the n-side contact electrode 13 on the back surface of the nP substrate 1 by, for example, an evaporation method, heat treatment is performed, and finally the n-side electrode 14 is formed so as to cover the n-contact electrode 13.

Strained InGaAs manufactured in this way
When light of 1.65 μm is incident on the back-illuminated APD having two light absorption layers 3 and 4 of InGaAs and InGaAs, the light passes through the InP substrate 1 and the InP buffer layer 2 from the lens 15 side on the back surface, and then the strain n -It is absorbed by the InGaAs light absorption layer 3. The carriers generated by the light absorbed here are accelerated by the electric field applied between the p-side electrode 12 and the n-electrode 14, flow into the p-side electrode 12, and are discharged to an external circuit to become a photocurrent.

On the other hand, when light of 1.55 μm or 1.3 μm is incident, the light passes through the InP substrate 1 and the InP buffer layer 2 from the lens 15 side on the back surface and then is strained n-InGaAs.
The light is absorbed by the light absorption layer 3 and the InGaAs light absorption layer 4. The carriers generated by the light absorbed here are accelerated by the electric field applied between the p-side electrode 12 and the n-electrode 14, flow into the p-side electrode 12, and are discharged to an external circuit to become a photocurrent. That is, the light of 1.55 / 1.3 μm is absorbed by the strained n-InGaAs light absorption layer 3 and the InGaAs light absorption layer 4, and the light of 1.65 μm is absorbed by the strained light absorption layer 3, and then photoelectrically converted. .

By adopting such a structure, 1.6
It becomes possible to absorb the light of 5 μm with high efficiency of 0.85 A / W or more, and to achieve high-speed response to the light of 1.55 / 1.3 μm. Further, since the lattice mismatch can be suppressed by sandwiching the strained n-InGaAs light absorption layer 3 between the InGaAs light absorption layer 5 and the InP substrate 1, a low dark current characteristic of 20 nA or less can be obtained.

Due to the above-described effects of this embodiment, the carriers generated in the strained n-InGaAs light absorption layer 3 or the InGaAs light absorption layer 4 are 30 by the electric field applied to the n ⁺ -InP multiplication layer 6. A high multiplication factor of more than twice can be obtained.

Further, the above-mentioned effects of this embodiment are obtained by the CVD method, the MO method, and the like in addition to the epitaxial wafer by the vapor phase growth method.
Similar effects can be obtained in epitaxial wafers formed by the CVD method, MBE method, and ALE method.

[0052]

As described above, according to the present invention,
It has various effects described below.

The first effect is that the light of 1.65 μm can be absorbed with a high efficiency of, for example, 0.85 A / W or more. This is, in the present invention,
Light of 1.65 μm is absorbed by the two layers of the InGaAs light absorption layer and the strained light absorption layer, so that high light receiving sensitivity can be obtained.

The second effect of the present invention is, for example, 20n.
This means that low dark current characteristics of A or less can be obtained.
According to the present invention, this is the InGaAs light absorption layer and In
This is because the lattice mismatch can be suppressed by sandwiching the strained n ⁻ -InGaAs light absorption layer with the P substrate.

The third effect of the present invention is that a high multiplication factor of 30 times or more can be obtained. This is the distortion n-I
This is because the carriers generated in the nGaAs light absorbing layer or the InGaAs light absorbing layer cause avalanche multiplication by the electric field applied to the n ⁺ -InP multiplication layer.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross section of an embodiment of a semiconductor light receiving element according to the present invention.

FIG. 2 is a diagram showing a sensitivity distribution of an example of a semiconductor light receiving element according to the present invention.

FIG. 3 is a diagram showing a cross section of a second embodiment of a semiconductor light receiving element according to the present invention.

FIG. 4 is a view showing a cross section of a conventional semiconductor light receiving element.

FIG. 5 is a view showing a cross section of another conventional semiconductor light receiving element.

[Explanation of symbols]

1 n ⁺ -InP substrate 2 n-InP buffer layer 3 strained n-InGaAs light absorption layer 4 n-InGaAs light absorption layer 5 n-InGaAsP intermediate layer 6 n ⁺ -InP multiplication layer 7 n ^-- InP window layer 8 guard Ring 9 p ⁺ region 10 Insulating film 11 p-side contact electrode 12 p-side electrode 13 n-side contact electrode 14 n-side electrode 15 lens with AR 16 Zn diffusion region 17 polyimide 18 Si ₃ N ₄ film 19 SiO ₂ film 20 Au / Zn Electrode 21 Au / Cr electrode 22 Au / Sn electrode 23 Relaxation layer 24 Strained lattice layer 25 Strained superlattice layer 26 InGaAs buffer layer 27 InAs / GaAs superlattice light absorption layer

Claims (6)

[Claims] 1. A first conductivity type strained InGaAs layer, a first conductivity type InGaAs layer, and a first conductivity type InP substrate on a first conductivity type InP substrate.
A heteroepitaxial layer structure in which a conductivity type InP multiplication layer and a first conductivity type InP window layer are sequentially formed,
Furthermore, a second conductivity type InP region is partially provided in the window layer and / or the multiplication layer, and a second conductivity type electrode is provided on the second conductivity type InP region in the window layer. A semiconductor light receiving element comprising: a first conductivity type electrode provided on the first conductivity type InP substrate; 2. The first conductivity type InGa layer has an absorption edge wavelength λ of 1.85 μm, and the first conductivity type InGa layer has an absorption edge wavelength λ of 1.85 μm.
2. The semiconductor light receiving element according to claim 1, wherein the absorption edge wavelength λ of the As layer is 1.65 μm. 3. The first conductive strained InGaAs layer has a layer thickness of 1 μm to 5 μm.
Alternatively, the semiconductor light receiving element according to item 2. 4. The first conductivity type strained InGaAs layer has a layer thickness of 1 μm to 3 μm.
Alternatively, the semiconductor light receiving element according to item 2. 5. The layer thickness of the first conductivity type InGaAs layer is 2
It consists of μm to 5 μm.
3. The semiconductor light receiving element according to any one of 3 above. 6. A first conductivity type InP substrate and a first conductivity type InG.
The first conductivity type strained InGaAs light absorption layer is inserted between the aAs light absorption layer and the introduced incident light of the first wavelength is absorbed by the first conductivity type InGaAs strained light absorption layer, and A semiconductor light receiving element characterized in that the incident light of a second wavelength, which is shorter than the incident light of the first wavelength, is absorbed by the first conductivity type InGaAs light absorption layer.