# US 5,346,837 A · Method of making avalanche photodiode

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- Number: US 5,346,837 A
- Document ID: US5346837A
- Status: Granted
- Kind: A
- Application number: 08/137,777
- Filed: 1993-10-19
- Granted: 1994-09-13
- Earliest claimed: 1991-04-18
- Assignees: Mitsubishi Denki Kabushiki Kaisha
- Inventors: Shinji Funaba
- Web page: https://patentgrep.com/patent/US5346837A

## CPC

- H10F 30/2255: {in which the active layers form heterostructures, e.g. SAM structures}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

A method of making an avalanche photodiode includes depositing a light-absorbing semiconductor layer of a first conductivity type on a semiconductor substrate of the first conductivity type; successively depositing multiple pairs of semiconductor layers on the light-absorbing layer, each of the pairs including a first semiconductor layer of the first conductivity type containing a first dopant impurity concentration and a second semiconductor layer of the first conductivity type containing a second dopant impurity concentration smaller than the first dopant impurity concentration; and forming a semiconductor light-receiving layer of a second conductivity type on the pairs of layers to form a pn junction with the pairs of layers.

## Claims

### Claim 1

A method of making an avalanche photodiode comprising the steps of:
depositing a light-absorbing semiconductor layer of a first conductivity type on a semiconductor substrate of the first conductivity type;
successively depositing a plurality of pairs of semiconductor layers on said light-absorbing layer, each of said pairs comprising a first semiconductor layer of the first conductivity type containing a first dopant impurity concentration and a second semiconductor layer of the first conductivity type containing second dopant impurity concentration smaller than the first dopant impurity concentration; and
forming a semiconductor light-receiving layer of a second conductivity type on said pairs of layers to form a pn junction with said pairs of layers.

### Claim 2 (depends on 1)

A method of making an avalanche photodiode according to claim 1 wherein the first layer in each pair of layers is located closer to said light-absorbing layer than the second layer in that pair.

### Claim 3 (depends on 2)

A method of making an avalanche photodiode according to claim 2 including forming said light-receiving region by selectively diffusing a dopant impurity into one of said second layers.