JPH0362976A - Semiconductor light-receiving device - Google Patents

Abstract

PURPOSE:To prevent light from inciding into an n<->-InGaAs light-absorbing layer and prevent deterioration of response characteristics by forming an n<->- InGaAs light-screening layer on an n<->-InP window layer. CONSTITUTION:When an inverse bias is applied between a P electrode 9 and an n electrode 10, incident light passing through a P<+>-InP window layer 5 is absorbed at an n<->-InGaAs light-absorbing layer 3, thus generating a carrier. This carrier generates optic current by separately drifting within a depletion layer which is extended in reverse bias.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor light receiving device with improved frequency characteristics.

[Conventional technology]

FIG. 2 is a sectional view of a conventional semiconductor light receiving device.

In the figure, (1) is n-1, P substrate, (2) is n--T
, lP buffer layer, (3) is n--1, G, As light absorption layer, (4) is n--1, P window layer, n-I, IP substrate (1
) have been grown sequentially. (5) is a selectively formed P'-1, P window layer, (6) is a P''-1fi P window layer (
5) At the same time, the P'-1,,G,A light absorption layer was selectively formed, (8) had an opening, and the nitride film was formed on the P'-I,,P window layer (5). , (9) is P"=P electrode partially formed on IlIP window layer (5), αω is n-L
This is an n-electrode formed on the +P substrate (1).

Next, the operation will be explained. P electrode (9) and n electrode 00
When a reverse bias is applied between P“−■.P window layer (5
) is mostly absorbed in the depletion layer extending into the n-1, Gm As light absorption layer (3) and generates carriers. Photocurrent is generated when these carriers drift due to the electric field in the depletion layer expanded by reverse bias.

[Problem to be solved by the invention]

Since the conventional semiconductor light-receiving device is constructed as described above, the light incident on the n-7G,A light absorption layer outside the depletion layer due to the reverse bias is absorbed and carriers are generated. However, since the movement of carriers is due to diffusion, it is much slower than that due to drift within the depletion layer, and this has been a cause of deterioration in response characteristics.

This invention was made to solve the above-mentioned problems, and it prevents light from entering the n--r, Ga At light absorption layer outside the depletion layer, and prevents the response characteristics from deteriorating. be.

[Means to solve the problem]

The semiconductor light receiving element according to the present invention has an n''-I.

An n--T, Gs At light blocking layer is formed on the P window layer.

[Effect]

The semiconductor photodetector according to the present invention prevents light from entering the n-1, Ga At light absorption layer outside the depletion layer by forming an n-I MGm Ag light blocking layer on the n-1°P window layer. The number of carriers that move only by diffusion can be reduced, and the deterioration of response characteristics can be prevented.

〔Example〕

An embodiment of this invention will be explained with reference to the drawings. FIG. 1 is a sectional view of a semiconductor light receiving device. In the figure (11-f6
Since 1181 to aω are the same as those shown in the conventional example of FIG. 2, their explanation will be omitted. (7) is n--IPPH14
), and has the same composition as the n--1r, CM A light absorption layer (3).

Next, the operation will be explained. P electrode (9) and n electrode fI
When a reverse bias is applied between I, the light passing through the P'-1, P window layer (5) is absorbed by the n--1, G A3 light absorption N (3) and generates carriers. . When these carriers separate and drift within the depletion layer expanded by reverse bias, a photocurrent is generated.

〔Effect of the invention〕

As described above, according to the present invention, by forming the n--19G, A, light blocking layer on the n--1,P window layer, the n--1,
--1, Gs As It is possible to prevent light from entering other than the depletion layer extending in the light absorption layer, it is possible to prevent the generation of slow moving carriers due to diffusion, and it is possible to prevent deterioration of response characteristics.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a semiconductor light receiving device according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional semiconductor light receiving device. In the figure, (1) is n-1, P substrate, (2) is n--1
fiP buffer layer,(3) is n--r,,G. A, light absorption layer, (4) is n--1, IP window layer, (5) is P"-1, P window layer, (6) is P"-1nG, A, light absorption layer, (7) is n”-I, lGm Ag light blocking layer, (
8) is a nitride film, (9) is a P electrode, and α0) is an n electrode. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] After sequentially forming an InP buffer layer having the same conductor, an InGaAs light absorption layer, and an InP window layer on the InP substrate having the first conductor, the InP buffer layer and the InGaAs
In a semiconductor light-receiving device having a structure in which a part of the light absorption layer is selectively inverted to a second conductor, an I in which the same conductor as the window layer is provided on the InP window layer of the first conductor;
A semiconductor light receiving device characterized by forming an nGaAs light blocking layer.