# US 11,309,347 B2 · Integrated circuit photodetector

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- Number: US 11,309,347 B2
- Document ID: US11309347B2
- Status: Granted
- Kind: B2
- Application number: 16/788,145
- Filed: 2020-02-11
- Published: 2021-08-12
- Granted: 2022-04-19
- Earliest claimed: 2020-02-11
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Chun-Wei Hsu; Tsai-Hao Hung; Chung-Yu Lin; Ying-Hsun Chen
- Web page: https://patentgrep.com/patent/US11309347B2

## CPC

- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/024: {of coatings or optical elements}
- H10F 39/8027: {Geometry of the photosensitive area}
- H10F 39/8063: {Microlenses}
- H10F 39/807: {Pixel isolation structures}
- H10F 39/809: {of hybrid image sensors}
- H10F 71/121: {The active layers comprising only Group IV materials}
- H10F 77/122: comprising only Group IV materials
- H10F 77/413: {directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42)}
- H10F 77/703: {of the semiconductor bodies, e.g. textured active layers}
- H10F 39/8037: {the integrated elements comprising a transistor}
- H10F 39/8067: {Reflectors}
- H10F 39/811: {Interconnections}
- H10F 71/1212: {consisting of germanium}
- H10F 71/1215: {comprising at least two Group IV elements, e.g. SiGe}
- H10F 71/1253: {comprising at least three elements, e.g. HgCdTe}
- H10F 71/1272: {comprising at least three elements, e.g. GaAlAs or InGaAsP}
- H10F 77/1237: {having at least three elements, e.g. HgCdTe}
- H10F 77/1248: {having three or more elements, e.g. GaAlAs, InGaAs or InGaAsP}
- H10F 77/127: {comprising only Group IV-VI or only Group II-IV-VI chalcogenide materials, e.g. PbSnTe}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

An integrated circuit includes a photodetector. The photodetector includes one or more dielectric structures positioned in a trench in a semiconductor substrate. The photodetector includes a photosensitive material positioned in the trench and covering the one or more dielectric structures. A dielectric layer covers the photosensitive material. The photosensitive material has an index of refraction that is greater than the indices of refraction of the dielectric structures and the dielectric layer.

## Claims

### Claim 1

An integrated circuit comprising:
a semiconductor substrate;
one or more dielectric structures of dielectric material protruding from a surface of the semiconductor substrate; and
a photosensitive material positioned on the semiconductor substrate and covering the one or more dielectric structures, wherein the photosensitive material has an index of refraction that is higher than an index of refraction of the dielectric material of the one or more dielectric structures; and
a layer of dielectric material covering the photosensitive material, the dielectric material of the layer of dielectric material having an index of refraction that is less than an index of refraction of the photosensitive material.

### Claim 2 (depends on 1)

The circuit of claim 1, wherein the one or more dielectric structures include silicon oxide or silicon nitride.

### Claim 3 (depends on 1)

The circuit of claim 1, wherein the layer of dielectric material includes silicon oxide or silicon nitride.

### Claim 4 (depends on 1)

The circuit of claim 1, wherein the photosensitive material is positioned in a trench formed in the semiconductor substrate.

### Claim 5 (depends on 4)

The circuit of claim 4, wherein the one or more dielectric structures protrude from a bottom of the trench.

### Claim 6 (depends on 5)

The circuit of claim 5, wherein the one or more dielectric structures include one or more columns extending from the bottom of the trench.

### Claim 7 (depends on 6)

The circuit of claim 6, wherein the columns terminate at or below a top of the trench.

### Claim 8 (depends on 6)

The circuit of claim 6, further comprising a dielectric sidewall covering of dielectric material positioned on a sidewall of the trench in contact with the photosensitive material, the dielectric material of the dielectric sidewall covering having an index of refraction that is less than the index of refraction of the photosensitive material.

### Claim 9 (depends on 1)

The circuit of claim 1, further comprising a lens configured to focus light on the photosensitive material.

### Claim 10 (depends on 1)

The circuit of claim 1, wherein the photosensitive material and the semiconductor substrate act as a photodetector that detects light by absorbing photons in the photosensitive layer and generating electrical signals indicative of the photons absorbed by the photosensitive material.

### Claim 11 (depends on 10)

The circuit of claim 10, wherein the photodetector is a photodiode.

### Claim 12 (depends on 1)

The circuit of claim 1, wherein the photosensitive material includes germanium.

### Claim 13

A device, comprising:
a semiconductor substrate including a plurality of trenches;
one or more dielectric structures of dielectric material protruding from a bottom surface of each trench;
a photosensitive material positioned in each trench covering the one or more dielectric structures and having an index of refraction greater than an index of refraction of the dielectric material of the one or more dielectric structures;
a plurality of lenses each configured to focus light onto the photosensitive material in a respective trench; and
a layer of dielectric material covering the photosensitive material in each trench, the dielectric material of the layer of dielectric material having an index of refraction that is lower than the index of refraction of the photosensitive material.

### Claim 14 (depends on 13)

The device of claim 13, further comprising a first integrated circuit including the semiconductor substrate and the photosensitive material.

### Claim 15 (depends on 14)

The device of claim 14, further comprising a second integrated circuit bonded to the first integrated circuit and including control circuitry configured to receive electrical signals from the photosensitive material responsive to light incident on the photosensitive material.

### Claim 16 (depends on 14)

The device of claim 14, wherein the first integrated circuit includes a plurality of transistors communicatively coupled to the photosensitive material.

### Claim 17

A method, comprising:
forming a trench in a semiconductor substrate;
forming one or more dielectric structures of dielectric material protruding from a bottom surface of the trench;
depositing a photosensitive material in the trench covering the one or more dielectric structures, wherein the photosensitive material has an index of refraction that is higher than an index of refraction the dielectric material of the one or more dielectric structures; and
depositing a layer of dielectric material on the photosensitive material, wherein the dielectric material of the layer of dielectric material has an index of refraction that is less than the index of refraction of the photosensitive material.

### Claim 18 (depends on 17)

The method of claim 17, wherein the semiconductor substrate and the photosensitive material collectively form a photodiode.

### Claim 19 (depends on 17)

The method of claim 17, further comprising depositing a dielectric sidewall coating of dielectric material on sidewalls of the trench, wherein depositing the photosensitive material includes covering the dielectric sidewall coating on the sidewalls of the trench with the photosensitive material.

### Claim 20 (depends on 19)

The method of claim 19, further comprising forming a lens configured to focus light onto the photosensitive material.