# US 11,309,447 B2 · Separate absorption charge and multiplication avalanche photodiode structure and method of making such a structure

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- Number: US 11,309,447 B2
- Document ID: US11309447B2
- Status: Granted
- Kind: B2
- Application number: 16/727,321
- Filed: 2019-12-26
- Published: 2021-07-01
- Granted: 2022-04-19
- Earliest claimed: 2019-12-26
- Assignees: GlobalFoundries U.S. Inc.
- Applicants: GLOBALFOUNDRIES U.S. Inc.
- Inventors: Ajey Poovannummoottil Jacob; Yusheng Bian
- Web page: https://patentgrep.com/patent/US11309447B2

## CPC

- H10F 30/2255: {in which the active layers form heterostructures, e.g. SAM structures}
- H10F 71/121: {The active layers comprising only Group IV materials}
- H10F 71/1215: {comprising at least two Group IV elements, e.g. SiGe}
- H10F 77/122: comprising only Group IV materials
- H10F 77/1433: {Quantum dots}
- H10F 77/1625: {Semiconductor nanoparticles embedded in semiconductor matrix}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

One illustrative photodiode disclosed herein includes an N-doped anode region, a P-doped cathode region and at least one P-doped charge region positioned laterally between the N-doped anode region and the P-doped cathode region. In this example, the photodiode also includes a plurality of quantum dots embedded within the at least one P-doped charge region and an N-doped impact ionization region positioned laterally between the N-doped anode region and the at least one P-doped charge region.

## Claims

### Claim 1

A photodiode, comprising:
an N-doped anode region, wherein the N-doped anode region is positioned within an active semiconductor layer;
a P-doped cathode region, wherein the P-doped cathode region is positioned within the active semiconductor layer;
at least one P-doped charge region positioned laterally between the N-doped anode region and the P-doped cathode region;
a plurality of quantum dots embedded within the at least one P-doped charge region; and
an N-doped impact ionization region positioned laterally between the N-doped anode region and the at least one P-doped charge region.

### Claim 2 (depends on 1)

The photodiode of claim 1, further comprising a semiconductor-on-insulator (SOI) that comprises a base semiconductor layer, a buried insulation layer positioned on the base semiconductor layer, and the active semiconductor layer, wherein the active semiconductor layer is positioned on the buried insulation layer, and wherein the N-doped anode region and the P-doped cathode region are positioned within the active semiconductor layer of the SOI.

### Claim 3 (depends on 1)

The photodiode of claim 1, wherein the N-doped anode region has a dopant concentration of an N-type dopant that falls within a range of 1E20-1E23 ions/cm3, the N-doped impact ionization region has a dopant concentration of an N-type dopant that falls within a range of 1E18-1E20 ions/cm3, the at least one P-doped charge region has a dopant concentration of a P-type dopant that falls within a range of 1E18-1E20 ions/cm3 and the P-doped cathode region has a dopant concentration of P-type dopant that falls within a range of 1E20-1E23 ions/cm3.

### Claim 4 (depends on 1)

The photodiode of claim 1, wherein at least one P-doped charge region comprises a plurality of P-doped charge regions, wherein each of the plurality of P-doped charge regions comprises a plurality of quantum dots embedded therein.

### Claim 5 (depends on 1)

The photodiode of claim 1, wherein, when viewed from above, the plurality of quantum dots embedded within the at least one P-doped charge region have one of an ordered pattern or a random pattern and one of a substantially circular, a substantially oval, or a substantially pyramidal configuration.

### Claim 6 (depends on 1)

The photodiode of claim 1, wherein the plurality of quantum dots embedded within the at least one P-doped charge region are doped with a P-type dopant.

### Claim 7 (depends on 1)

The photodiode of claim 1, wherein the plurality of quantum dots embedded within the at least one P-doped charge region comprise one of a silicon-containing semiconductor material, a germanium-containing semiconductor material, silicon germanium, substantially pure silicon or substantially pure germanium.

### Claim 8 (depends on 1)

The photodiode of claim 1, further comprising a region of a substantially un-doped intrinsic semiconductor material positioned laterally between the at least one P-doped charge region and the P-doped cathode region.

### Claim 9 (depends on 8)

The photodiode of claim 8, further comprising a P-doped implant region positioned laterally between the N-doped impact ionization region and the region of a substantially un-doped intrinsic semiconductor material and vertically below the at least one P-doped charge region.

### Claim 10 (depends on 1)

The photodiode of claim 1, further comprising a P-doped implant region positioned vertically below the at least one P-doped charge region.

### Claim 11 (depends on 1)

The photodiode of claim 1, wherein the N-doped impact ionization region abuts and engages the N-doped anode region and the at least one P-doped charge region abuts and engages the N-doped impact ionization region.

### Claim 12 (depends on 11)

The photodiode of claim 11, further comprising a region of a substantially un-doped intrinsic semiconductor material positioned laterally between the at least one P-doped charge region and the P-doped cathode region, wherein the P-doped charge region abuts and engages the region of a substantially un-doped intrinsic semiconductor material and wherein the region of a substantially un-doped intrinsic semiconductor material abuts and engages the P-doped cathode region.

### Claim 13 (depends on 1)

The photodiode of claim 1, wherein the plurality of quantum dots have a tensile strain.

### Claim 14

A photodiode, comprising:
a semiconductor-on-insulator (SOI) that comprises a base semiconductor layer, a buried insulation layer positioned on the base semiconductor layer and an active semiconductor layer positioned on the buried insulation layer;
an N-doped anode region positioned within the active semiconductor layer;
a P-doped cathode region positioned within the active semiconductor layer;
at least one P-doped charge region positioned within the active semiconductor layer and laterally between the N-doped anode region and the P-doped cathode region;
a plurality of quantum dots embedded within the at least one P-doped charge region; and
an N-doped impact ionization region positioned in the active semiconductor layer laterally between the N-doped anode region and the at least one P-doped charge region.

### Claim 15 (depends on 14)

The photodiode of claim 14, wherein the at least one P-doped charge region comprises a plurality of P-doped charge regions, wherein at least some of the plurality of P-doped charge regions are positioned in the active semiconductor layer and wherein each of the plurality of P-doped charge regions has a plurality of quantum dots embedded therein.

### Claim 16 (depends on 14)

The photodiode of claim 14, wherein, when viewed from above, the plurality of quantum dots embedded within the at least one P-doped charge region have one of an ordered pattern or a random pattern and one of a substantially circular or a substantially oval configuration, wherein the plurality of quantum dots embedded within the at least one P-doped charge region are doped with a P-type dopant and wherein the plurality of quantum dots comprise one of a silicon-containing semiconductor material, a germanium-containing semiconductor material, silicon germanium, substantially pure silicon or substantially pure germanium.

### Claim 17 (depends on 14)

The photodiode of claim 14, further comprising a region of a substantially un-doped intrinsic semiconductor material layer positioned in the active semiconductor layer and laterally between the at least one P-doped charge region and the P-doped cathode region.

### Claim 18 (depends on 17)

The photodiode of claim 17, further comprising a P-doped implant region positioned in the active semiconductor layer laterally between the N-doped impact ionization region and the region of a substantially un-doped intrinsic semiconductor material and vertically below the at least one P-doped charge region.

### Claim 19 (depends on 17)

The photodiode of claim 17, wherein the N-doped impact ionization region abuts and engages the N-doped anode region, the at least one P-doped charge region abuts and engages the N-doped impact ionization region, the at least one P-doped charge region abuts and engages the region of a substantially un-doped intrinsic semiconductor material and the region of a substantially un-doped intrinsic semiconductor material abuts and engages the P-doped cathode region.

### Claim 20

A photodiode, comprising:
a semiconductor-on-insulator (SOI) that comprises a base semiconductor layer, a buried insulation layer positioned on the base semiconductor layer and an active semiconductor layer positioned on the buried insulation layer, wherein the active semiconductor layer comprises silicon or silicon germanium;
an N-doped anode region positioned within the active semiconductor layer;
a P-doped cathode region positioned within the active semiconductor layer;
at least one P-doped charge region positioned within the active semiconductor layer and laterally between the N-doped anode region and the P-doped cathode region;
a plurality of germanium quantum dots embedded within the at least one P-doped charge region, wherein each of the germanium quantum dots has a tensile strain;
an N-doped impact ionization region positioned in the active semiconductor layer laterally between the N-doped anode region and the at least one P-doped charge region; and
a region of a substantially un-doped intrinsic semiconductor material layer positioned in the active semiconductor layer and laterally between the at least one P-doped charge region and the P-doped cathode region.