# US 12,765,099 B2 · Photodiode with deep trench isolation structures

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- Number: US 12,765,099 B2
- Document ID: US12765099B2
- Status: Granted
- Kind: B2
- Application number: 18/064,890
- Filed: 2022-12-12
- Published: 2024-06-13
- Granted: 2026-10-13
- Earliest claimed: 2022-12-12
- Assignees: Globalfoundries Singapore Pte. Ltd.
- Applicants: GlobalFoundries Singapore Pte. Ltd.
- Inventors: Ping Zheng; Eng Huat Toh; Cancan Wu; Kiok Boone Elgin Quek
- Web page: https://patentgrep.com/patent/US12765099B2

## CPC

- H10F 39/807: {Pixel isolation structures}
- H10F 39/011: {Manufacture or treatment of image sensors covered by group H10F39/12}
- H10F 39/805: {Coatings}
- H10F 39/8063: {Microlenses}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

A photodiode device includes a semiconductor substrate, a plurality of pixels, each of the pixels including a diode structure on a first side of the substrate and a conductive layer on a second side of the substrate, and DTI structures isolating adjacent pixels from one another, the DTI structures including a conductive material that electrically couples the conductive layer on the second side of the substrate and a metal line on the first side of the substrate. The conductive material in the DTI structures is part of an electrode circuit for the pixels.

## Claims

### Claim 1

A photodiode device, comprising:
a semiconductor substrate;
a plurality of pixels, each of the pixels including a diode structure on a first side of the semiconductor substrate and a conductive layer on a second side of the semiconductor substrate;
deep trench isolation (DTI) structures isolating adjacent pixels from one another, the DTI structures including a conductive material electrically coupled to the conductive layer on the second side of the substrate and a metal line on the first side of the semiconductor substrate;
an insulation liner layer disposed over sidewalls of trenches within the DTI structures, wherein the conductive material includes a first shoulder that overlaps upper edges of the insulation liner layer; and
an anti-reflective layer over the conductive layer,
wherein the conductive material extends through an entire thickness of the conductive layer, and a sidewall of the first shoulder contacts the conductive layer, and
wherein the conductive material further comprises a second shoulder above the first shoulder, and the second shoulder overlaps a portion of the anti-reflective coating layer.

### Claim 2 (depends on 1)

The photodiode device of claim 1, wherein the conductive layer is an electrode of the respective pixel.

### Claim 3 (depends on 1)

The photodiode device of claim 1, further comprising contacts coupled to the conductive material within the DTI structures and disposed on the first side of the semiconductor substrate at a base of the trenches.

### Claim 4 (depends on 3)

The photodiode device of claim 3, wherein the contacts extend through an etch stop layer and an interlayer dielectric layer.

### Claim 5 (depends on 1)

The photodiode device of claim 1, wherein the photodiode device is a single-photon avalanche diode.

### Claim 6 (depends on 1)

The photodiode device of claim 1, wherein the diode structure includes a first doped region, a first doped well over the first doped region, and a second doped well over the first doped well,
the first doped region and first doped well are doped with a first type of dopants, and
the second doped well and the conductive layer are doped with a second type of dopants.

### Claim 7 (depends on 1)

The photodiode device of claim 1, further comprising:
a plurality of micro-lenses over the anti-reflective coating,
wherein the conductive material extends through the anti-reflective coating layer.

### Claim 8

A photodetector, comprising:
a photodiode device; and
a control circuit configured to control an operation of the photodiode device,
wherein the photodiode device includes:
a semiconductor substrate;
a plurality of pixels, each of the pixels including a diode structure on a first side of the semiconductor substrate and a conductive layer on a second side of the semiconductor substrate;
deep trench isolation (DTI) structures isolating adjacent pixels from one another, the DTI structures including a conductive material electrically coupled to the conductive layer on the second side of the substrate and a metal line on the first side of the semiconductor substrate;
an anti-reflective layer over the conductive layer; and
an insulation liner layer disposed over sidewalls of trenches within the DTI structures, wherein conductive material includes a first shoulder that overlaps upper edges of the insulation liner layer,
wherein the conductive material extends through an entire thickness of the conductive layer, and a sidewall of the first shoulder contacts the conductive layer, and
wherein the conductive material further comprises a second shoulder above the first shoulder, and the second shoulder overlaps a portion of the anti-reflective coating layer.

### Claim 9 (depends on 8)

The photodetector of claim 8, wherein the conductive layer is an electrode of the respective pixel.

### Claim 10 (depends on 8)

The photodetector of claim 8, further comprising contacts coupled to the conductive material within the DTI structures and disposed on the first side of the semiconductor substrate at a base of the trenches.

### Claim 11 (depends on 10)

The photodetector of claim 10, wherein the contacts extend through an etch stop layer and an interlayer dielectric layer.

### Claim 12 (depends on 8)

The photodetector of claim 8, wherein the photodiode device is a single-photon avalanche diode.

### Claim 13

A method of forming a photodiode device, the method comprising:
providing a semiconductor substrate with first and second sides, the semiconductor substrate including a plurality of diode structures on the first side of the substrate respectively associated with a plurality of pixels, and a conductive layer on the second side of the substrate; and
forming deep trench isolation (DTI) structures isolating adjacent pixels from one another, the DTI structures including a conductive material that electrically couples the conductive layer on the second side of the substrate and a metal line on the first side of the semiconductor substrate; and
forming an anti-reflective layer over the conductive layer,
wherein forming the DTI structures includes:
forming trenches in the semiconductor substrate; and
depositing an insulation liner layer over sidewalls of the trenches,
wherein an upper portion of the trenches is exposed by the insulation layer so that the conductive material is electrically coupled to the conductive layer in the upper portion of the trenches, and
wherein a portion of the conductive material includes a first shoulder that overlaps upper edges of the insulation liner layer,
wherein the conductive material further comprises a second shoulder above the first shoulder, and the second shoulder overlaps a portion of the anti-reflective coating layer, and
wherein the conductive material extends through an entire thickness of the conductive layer, and a sidewall of the first shoulder contacts the conductive layer.

### Claim 14 (depends on 13)

The method of claim 13, wherein the conductive material in the DTI structures is coupled to contacts disposed at the base of the trenches.

### Claim 15 (depends on 14)

The method of claim 14, wherein the contacts at the base of the trenches are coupled to the metal lines, and the conductive layer on the second side of the substrate, the conductive material of the DTI structures, the contacts and the metal lines are part of a circuit for the pixel.

### Claim 16 (depends on 13)

The method of claim 13, further comprising:
forming the diode structures on the first side of the semiconductor substrate, the semiconductor substrate having a buried doped layer on the second side.

### Claim 17 (depends on 1)

The photodiode device of claim 1, wherein the conductive layer is a doped semiconductor material.

### Claim 18 (depends on 1)

The photodiode device of claim 1, wherein the conductive material is a doped semiconductor material.