# US 7,411,265 B2 · Photodiode and phototransistor

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- Number: US 7,411,265 B2
- Document ID: US7411265B2
- Status: Granted
- Kind: B2
- Application number: 11/463,347
- Filed: 2006-08-09
- Published: 2007-02-15
- Granted: 2008-08-12
- Earliest claimed: 2005-08-09
- Assignees: Rohm Co., Ltd.
- Inventors: Yushi Sekiguchi
- Web page: https://patentgrep.com/patent/US7411265B2

## CPC

- H10F 30/222: the potential barrier being a PN heterojunction
- H10F 77/147: {Shapes of bodies}
- Y02E 10/50: Photovoltaic [PV] energy
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A phototransistor includes a first-conduction-type lower region, a second-conduction-type upper region disposed on the first region, a second-conduction-type electrode contact region of a high concentration disposed at a surface inside of the upper region and is connected to an electrode so as to transmit a signal, a first-conduction-type first shield region of a high concentration disposed at the surface of the upper region and spaced at an interval from the electrode contact region and connected to a ground potential, and a first-conduction-type second shield region of a low concentration disposed between the electrode contact region and the first shield region at the surface of the upper region so as to surround the electrode contact region, and further, is connected to the ground potential.

## Claims

### Claim 1

A photodiode comprising:
a first-conduction-type lower region;
a second-conduction-type upper region arranged on the lower region;
a second-conduction-type electrode contact region of a high concentration arranged at a surface of the upper region, the second-conduction-type electrode contact region arranged to connect to an electrode so as to transmit an output signal;
a first-conduction-type first electromagnetic shield region of a high concentration arranged at the surface of the upper region and spaced by an interval from the electrode contact region, wherein the first-conduction-type first shield region is connected to a ground potential; and
a first-conduction-type second electromagnetic shield region of a low concentration arranged between the electrode contact region and the first shield region at the surface of the upper region so as to surround the electrode contact region; wherein
the first-conduction-type second shield region is connected to the ground potential.

### Claim 2 (depends on 1)

A phototransistor comprising:
a device separation region arranged to surround a photodiode region;
the photodiode according to claim 1 arranged inside of the photodiode region; and
an output transistor arranged outside of the photodiode region and separated from the photodiode via the device separation region, wherein the output transistor is arranged to amplify a signal to be output from the photodiode.

### Claim 3 (depends on 2)

The phototransistor according to claim 2, wherein the electrode contact region is arranged at a peripheral edge of the photodiode region and adjacent to the device separation region.

### Claim 4 (depends on 3)

The phototransistor according to claim 3, wherein the device separation region includes a trench extending from the surface of the upper region in a direction towards the lower region, and the phototransistor further comprises a first-conduction-type connection region arranged to connect the second shield region and the lower region to each other along the trench.

### Claim 5 (depends on 4)

The phototransistor according to claim 4, wherein the connection region is provided on an entire circumference of an interface between the trench and the upper region, and the first shield region is connected to the lower region via the connection region.