# US 2018/0277697 A1 · Photodetector with reduced dark current

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- Number: US 2018/0277697 A1
- Document ID: US20180277697A1
- Status: Published application
- Kind: A1
- Application number: 15/761,051
- Filed: 2016-09-15
- Published: 2018-09-27
- Earliest claimed: 2015-09-16
- Assignees: Societe Francaise de Detecteurs Infrarouges-Sofradir
- Applicants: SociéTé FrançAise De DéTecteurs Infrarouges - Sofradir
- Inventors: Laurent RUBALDO; Nicolas PERE LAPERNE; Alexandre KERLAIN; Alexandru NEDELCU
- Web page: https://patentgrep.com/patent/US20180277697A1

## CPC

- H10F 77/143: {comprising quantum structures}
- H10F 30/21: the devices being sensitive to infrared, visible or ultraviolet radiation
- H10F 30/2215: {the devices comprising active layers made of only Group III-V materials}
- H10F 77/146: {Superlattices; Multiple quantum well structures}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

The photodetector includes a photon absorbing region formed by a first semiconductor material having a first bandgap energy value. It also includes a blocking region formed by at least second and third semiconductor materials configured to prevent the majority charge carriers from passing between the photon absorbing region and a contact region, the second semiconductor material presenting a second bandgap energy value higher than the first bandgap energy value to form a quantum well with the third semiconductor material. The blocking region is doped.

## Claims

### Claim at position 1

1-17. (canceled)

### Claim 18

Photodetector, comprising:
a photon absorbing region formed by a first semiconductor material having a first bandgap energy value,
a contact region made from semiconductor material,
a blocking region formed by at least a second semiconductor material configured to oppose flow of the majority charge carriers between the photon absorbing region and the contact region, the second semiconductor material presenting a second bandgap energy value higher than the first bandgap energy value,
wherein the blocking region is doped and configured to form at least one quantum well by means of the second semiconductor material and a third semiconductor material having a third bandgap energy value different from the second bandgap energy value.

### Claim 19 (depends on 18)

Photodetector according to claim 18, wherein the thickness of the second semiconductor material is at least twice that of the thickness of the third semiconductor material.

### Claim 20 (depends on 18)

Photodetector according to claim 18, wherein the blocking region is configured to be devoid of mini-bands.

### Claim 21 (depends on 18)

Photodetector according to claim 18, wherein the blocking region comprises a fourth semiconductor material presenting a fourth bandgap energy value higher than the first bandgap energy value and different from the second bandgap energy value and from the third bandgap energy value.

### Claim 22 (depends on 18)

Photodetector according to claim 18, including a substrate comprising the photon absorbing region, the blocking region, the contact region and a support region, and in that the support region is separated from the contact region by the photon absorbing region and the blocking region.

### Claim 23 (depends on 22)

Photodetector according to claim 22, further comprising:
an additional contact region and
an additional blocking region arranged between the photon absorbing region and the additional contact region, the additional blocking region being configured to block the minority charge carriers between the photon absorbing region and the additional contact region.

### Claim 24 (depends on 23)

Photodetector according to claim 23, wherein the additional contact region is located between the support region and the photon absorbing region.

### Claim 25 (depends on 23)

Photodetector according to claim 23, wherein the additional blocking region comprises at least one quantum well made from fifth and sixth semiconductor materials respectively presenting fifth and sixth bandgap energy values, the fifth and/or sixth bandgap energy value being higher than the first bandgap energy value.

### Claim 26 (depends on 18)

Photodetector according to claim 18, wherein the first semiconductor material is identical to the third semiconductor material and/or to the fifth semiconductor material.

### Claim 27 (depends on 18)

Photodetector according to claim 18, wherein the blocking region and/or the additional blocking region are doped over their whole thickness.

### Claim 28 (depends on 18)

Photodetector according to claim 18, wherein the blocking region defines one or more potential well regions and several potential barrier regions and wherein the blocking region is doped only in one or more of said potential well regions.

### Claim 29 (depends on 18)

Photodetector according to claim 18, wherein the blocking region defines one or more potential well regions and several potential barrier regions and wherein the blocking region is doped only outside the potential well region or regions.

### Claim 30 (depends on 18)

Photodetector according to claim 18, wherein the blocking region comprises an alternation of layers of second semiconductor material and of third semiconductor material and wherein the layers of second semiconductor material are tensile stressed and the layers of third semiconductor material are compressive stressed.

### Claim 31 (depends on 18)

Photodetector according to claim 18, wherein the blocking region comprises between 1 and 10 quantum wells.

### Claim 32 (depends on 18)

Photodetector according to claim 18, wherein the blocking region is in direct contact with the photon absorbing region.

### Claim 33 (depends on 18)

Photodetector according to claim 18, wherein the blocking region is in direct contact with the contact region.