JPH022185A - Semiconductor photosensitive element - Google Patents

Abstract

PURPOSE:To increase an effective area of a p-n junction and to improve photoelectric efficiency by providing an n-type buried layer on a p-type substrate, by providing a p-type buried layer on the n-type buried layer, by making an n-type epitaxial layer grow on the surface thereof, and by providing p-type diffusion layer whose one end is connected to a p-type isolation diffusion layer on the epitaxial layer. CONSTITUTION:An n-type buried layer 2 is provided on a p-type substrate 1, a p-type buried layer 3 is provided on the n-type buried layer 2, and an n-type epitaxial layer 4 is formed on the surface thereof. A p-type isolation diffusion layer 5 is provided so that its one end is connected to the p-type buried layer 3 and attains to the p-type substrate 1. The n-type epitaxial layer 4 is provided with a p-type diffusion layer 6 whose one end is connected to the p-type isolation diffusion layer 5. Ohmic contact electrodes 8, 9 are provided to each of an n<+> diffusion layer 7 and p-type diffusion layers 5, 6 which are provided to the n-type epitaxial layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor light receiving element that detects light by converting light into an electrical signal at a PN junction.

[Conventional technology]

FIG. 3 shows an example of a conventional semiconductor light receiving element.

An n-type epitaxial layer 4 is grown on a p-type substrate 1, a p-type diffusion layer 6 whose one end is connected to the p-type diffusion layer 5 is provided on the n-type epitaxial layer 4, and an n-type epitaxial layer 4 is grown on the p-type substrate 1. An n+ diffusion layer 7 is provided in the layer 4, and the n+ diffusion layer 7 and p
Ohmink contact electrodes 8 and 9 are provided in the type diffusion layers 5 and 6, respectively, and a voltage is applied to the voltages 8 and 9 so that the PN junction becomes reverse biased. ) to detect light by observing changes in reverse current due to photoelectric conversion.

[Problem to be solved by the invention]

In the conventional semiconductor light-receiving device having the above structure, the PN junction that is effective for incident light from above is the p-type diffusion layer 6.
．． p-type substrate I. Type shrimp! Ya, ya.

There was a problem in that the photoelectric conversion efficiency was only 9 good with only the two M planes formed by the layer 4.

The present invention has been made in view of the above problems, and its entire purpose is to provide improved photoelectric conversion efficiency.

[Means to solve division problems]

In the semiconductor photodetector of the present invention, an n-type buried layer is provided on a p-type substrate, and after the entire p-type buried layer is fully formed adjacent to the n-type buried layer, the surface An n-type epitaxial layer is grown on the n-type epitaxial layer, and a p-type diffusion layer is provided on the n-type epitaxial layer, one end of which connects to the p-type isolation diffusion layer, so that the surface of the PN junction is effective for incident light from above. A structure in which two or more overlap: This is a strained structure.

〔Example〕

FIG. 1 shows an embodiment of the invention.

An n-type buried layer 2 is provided on a p-type substrate 1, an n-type buried layer 3 is provided adjacently on the n-type buried layer 2, and a surface lζ is formed. Grow a p-type isolation/diffusion layer 4, and grow a p-type isolation diffusion layer 5.
is connected to one end of the n-type buried layer 3 and reaches the p-type substrate 1, and a p-type diffusion layer 6 whose one end is connected to the p-type ainlay/yon diffusion layer 5 is provided in the n-type epitaxial layer 1. provided, n
Ohmic contact electrodes 8 and 9 are provided on the n+ diffusion layer 7 and the p-type diffusion layers 5 and 6 provided in the type Evitacal layer 4, respectively.

Four effective PN junction surfaces overlap with each other for incident light from above, increasing the area of the effective PN junction and improving photoelectric conversion efficiency compared to the conventional structure.

FIG. 2 shows release from a substrate similar to that shown in FIG.

The n-type buried layer 3 and the p-type diffusion layer 6 are separated from the p-type ein-rayon diffusion layer 5, and the n-type buried layer 3 and the p-type diffusion layer 6 are formed into a p-diffusion layer 5a (p-type isolation diffusion layer). (formed in the diffusion process in step 5).

There are three surfaces of the PN junction that are effective for incident light from above.

〔Effect of the invention〕

As explained above, according to the present invention, three or more surfaces of the PN junction that are effective against the incident light from above overlap, resulting in higher photoelectric conversion efficiency than the conventional one and miniaturization of the device. There is.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing one embodiment of the present invention, and Fig. 2 is a schematic diagram showing an embodiment of the present invention.
FIG. 3 is a schematic diagram showing an example of a conventional semiconductor light-receiving device. DESCRIPTION OF SYMBOLS 1...p-type substrate, 2...n-type buried layer, 3...p-type buried layer, 4...n-type epitaxial layer, 5...p-type ain laser diffusion layer, 6...・P-type diffusion layer, 7...
・N diffusion layer, 8, 9...electrode. Note that the same reference numerals in the figures indicate the same or corresponding parts. P-type isolation diffusion layer patent applicant New Japan Radio Co., Ltd. Figure 2

Claims (1)

[Claims] In a semiconductor light-receiving element that detects light by converting light into an electrical signal at a PN junction, an n-type buried layer is provided on a p-type substrate,
A p-type buried layer is provided adjacent to the n-type buried layer, and an n-type buried layer is provided on the surface.
a p-type epitaxial layer is grown, a p-type isolation diffusion layer is provided on the n-type epitaxial layer, one end of which is connected to one end of the p-type buried layer and reaches the p-type substrate, and one end of the n-type epitaxial layer is connected to the p-type buried layer. 1. A semiconductor light-receiving element characterized in that a p-type diffusion layer connected to an isolation diffusion layer is provided, and two or more surfaces of a PN junction part that are effective against incident light from above overlap.