# US 10,483,426 B2 · Photo cell devices for phase-sensitive detection of light signals

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- Number: US 10,483,426 B2
- Document ID: US10483426B2
- Status: Granted
- Kind: B2
- Application number: 14/880,680
- Filed: 2015-10-12
- Published: 2016-03-17
- Granted: 2019-11-19
- Earliest claimed: 2011-12-21
- Assignees: Infineon Technologies AG
- Applicants: Infineon Technologies AG
- Inventors: Thoralf Kautzsch
- Web page: https://patentgrep.com/patent/US10483426B2

## CPC

- H10F 39/107: {having multiple elements covered by H10F30/00 in a repetitive configuration, e.g. radiation detectors comprising photodiode arrays}
- G01S 7/4861: Circuits for detection, sampling, integration or read-out
- H10F 30/221: the potential barrier being a PN homojunction
- H10F 30/28: the devices being characterised by field-effect operation, e.g. junction field-effect phototransistors
- H10F 77/148: {Shapes of potential barriers}
- H10F 77/957: {for position-sensitive photodetectors, e.g. lateral-effect photodiodes or quadrant photodiodes}
- Y02E 10/50: Photovoltaic [PV] energy
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Embodiments relate to photo cell devices. In one embodiment, a trench-based photo cells provides very fast capture of photo-generated charge carriers, particularly when compared with conventional approaches, as the trenches of the photo cells create depleted regions deep within the bulk of the substrate that avoid the time-consuming diffusion of carriers.

## Claims

### Claim 1

A method comprising:
providing a first vertical trench in a substrate; and
providing a second vertical trench in the substrate laterally disposed from the first vertical trench, wherein a horizontal extent of the first and second vertical trenches extend in a first direction such that the first and second vertical trenches run in the first direction parallel to one another;
providing a third vertical trench in the substrate;
providing a fourth vertical trench in the substrate laterally disposed from the third vertical trench, wherein a horizontal extent of the third and fourth vertical trenches extend in a second direction generally perpendicular to the first direction, such that the third and fourth vertical trenches run in the second direction parallel to one another,
wherein the first vertical trench, the second vertical trench, the third vertical trench and the fourth vertical trench collectively substantially enclose and thus define a square region of the substrate therebetween;
alternately depleting a first region of the substrate surrounding the first vertical trench and a second region of the substrate surrounding the second vertical trench by alternately applying a voltage to a first vertical trench gate contact and a second vertical trench gate contact, and
alternately depleting a third region of the substrate surrounding the third vertical trench and a fourth region of the substrate surrounding the fourth vertical trench by alternately applying a voltage to a third vertical trench gate contact and a fourth vertical trench gate contact,
wherein the alternate depleting of the first, second, third and fourth regions comprising an interleaved biasing resulting in biasing of the various trenches serially in a circular fashion,
wherein a lateral distance separating the first vertical trench and the second vertical trench is related to a doping level of the substrate such that upon operation a biasing of one of the first vertical trench, the second vertical trench, the third vertical trench and the fourth vertical trench results in formation of a fully depleted gap in a region centrally located between the first vertical trench, the second vertical trench, the third vertical trench, and the fourth vertical trench.

### Claim 2 (depends on 1)

The method of claim 1, wherein the voltage is a positive voltage, and the substrate is p-doped.

### Claim 3 (depends on 1)

The method of claim 1, wherein the voltage is a negative voltage, and the substrate is n-doped.

### Claim 4 (depends on 1)

The method of claim 1, further comprising comparing a charge at the first vertical trench gate contact and the second vertical trench gate contact.

### Claim 5 (depends on 1)

The method of claim 1, wherein first and second vertical trenches each extends at least about 5 microns into the substrate.

### Claim 6 (depends on 1)

The method of claim 1, wherein first and second vertical trenches each extends at least about 30 microns into the substrate.