# US 10,770,505 B2 · Per-pixel performance improvement for combined visible and ultraviolet image sensor arrays

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- Number: US 10,770,505 B2
- Document ID: US10770505B2
- Status: Granted
- Kind: B2
- Application number: 15/479,722
- Filed: 2017-04-05
- Published: 2018-10-11
- Granted: 2020-09-08
- Earliest claimed: 2017-04-05
- Assignees: Intel Corporation
- Applicants: Intel Corporation
- Inventors: Richmond Hicks; Khaled Ahmed
- Web page: https://patentgrep.com/patent/US10770505B2

## CPC

- H10F 39/184: {Infrared image sensors}
- H10F 39/014: {of CMOS image sensors}
- H10F 39/024: {of coatings or optical elements}
- H10F 39/182: {Colour image sensors}
- H10F 39/199: {Back-illuminated image sensors}
- H10F 39/8023: {Disposition of the elements in pixels, e.g. smaller elements in the centre of the imager compared to larger elements at the periphery}
- H10F 39/8053: {Colour filters}
- H10F 39/811: {Interconnections}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

Per-pixel performance is improved in a combined visible and ultraviolet image sensor array such as for a hyperspectral camera. In one example, an array of photodetectors is formed on a silicon substrate. A subset of the photodetectors are improved to improve sensitivity to ultraviolet light, and the photodetector array is finished to form an image sensor.

## Claims

### Claim 1

An image sensor comprising:
a silicon substrate;
a first set of photodetectors on the silicon substrate that have a thin layer that is conductive and is disposed over an active area and that generates a static electrical charge over an n-well of the first set of photodetectors to detect ultra-violet light;
a second set of photodetectors on the silicon substrate that do not have the thin layer to detect light that is other than ultra-violet light; and
an optical system to direct visible and infrared light to the first and the second sets of photodetectors.

### Claim 2 (depends on 1)

The image sensor of claim 1, wherein the thin layer comprises a doped semiconductor layer.

### Claim 3 (depends on 1)

The image sensor of claim 1, wherein the thin layer has a thickness of less than 3 nm.

### Claim 4 (depends on 1)

The image sensor of claim 1, wherein the first and second sets of photodetectors form an array that is formed on a back side of the silicon substrate.

### Claim 5 (depends on 4)

The image sensor of claim 4, further comprising circuit layers on a front side of the silicon substrate opposite the optical system.

### Claim 6

A portable computing system comprising:
a processor;
a communications chip coupled to the processor to send and receive images; and
an image sensor coupled to the processor having a silicon substrate, a first set of photodetectors on the silicon substrate that have a thin layer that is conductive and is disposed over an active area that generates a static electrical charge over an n-well of the first set of the photodetectors to detect ultra-violet light, a second set of photodetectors on the silicon substrate that do not have the thin layer to detect light other than ultra-violet light, and an optical system to direct visible and infrared light to the first and the second sets of photodetectors.

### Claim 7 (depends on 6)

The system of claim 6, wherein the first set of photodetectors has a δ-doped layer of p-type silicon over an n-well of the subset of photodetectors.

### Claim 8 (depends on 6)

The system of claim 6, wherein the first set of photodetectors is distributed across the sensor in a repeating pattern with the second set of photodetectors.

### Claim 9

A camera comprising:
an image sensor array comprising:
a silicon substrate,
a first set of photodetectors on the silicon substrate that have a thin layer that is conductive and is disposed over an active area and that generates a static electrical charge over an n-well of the first set of photodetectors to detect ultra-violet light,
a second set of photodetectors on the silicon substrate that do not have the thin layer to detect other than ultra-violet light, and
an optical system to direct visible and infrared light to the first and the second sets of photodetectors.

### Claim 10 (depends on 9)

The camera of claim 9, wherein the thin layer comprises a doped semiconductor layer.

### Claim 11 (depends on 9)

The camera of claim 9, wherein the thin layer has a thickness of less than 3 nm.

### Claim 12 (depends on 9)

The camera of claim 9, wherein the array is formed on a back side of the silicon substrate.

### Claim 13 (depends on 12)

The camera of claim 12, further comprising circuit layers on a front side of the silicon substrate opposite the optical system.

### Claim 14 (depends on 9)

The camera of claim 9, wherein the first set of photodetectors has a δ-doped layer of p-type silicon over an n-well of the subset of photodetectors.

### Claim 15 (depends on 9)

The camera of claim 9, wherein the first set of photodetectors is distributed across the array in a repeating pattern with the second set of photodetectors.

### Claim 16

An image sensor comprising:
a silicon substrate;
a first set of photodetectors on the silicon substrate that have a thin layer that is conductive and is disposed over an active area and that generates an electric field arranged to move electrons toward a depletion layer on the photodetectors to detect ultra-violet light;
a second set of photodetectors with n-wells on the silicon substrate that do not have the thin layer to detect light other than ultra-violet light;
an optical system to direct visible and infrared light to the first and the second sets of photodetectors.

### Claim 17 (depends on 16)

The image sensor of claim 16 wherein the electric field forms a static electrical charge.

### Claim 18 (depends on 16)

The image sensor of claim 16 wherein the thin layer is disposed over an n-well on the photodetectors, and the depletion layer forms a bottom of the n-well.

### Claim 19 (depends on 1)

The image sensor of claim 1 wherein the second set of photodetectors on the silicon substrate each have an n-well.

### Claim 20 (depends on 6)

The system of claim 6 wherein the second set of photodetectors on the silicon substrate each have an n-well.

### Claim 21 (depends on 9)

The camera of claim 9 wherein the second set of photodetectors on the silicon substrate each have an n-well.

### Claim 22 (depends on 1)

The image sensor of claim 1 wherein the second set of photodetectors detects red, green, blue, or infra-red (IR) light.

### Claim 23 (depends on 6)

The system of claim 6 wherein the second set of photodetectors detects red, green, blue, or infra-red (IR) light.

### Claim 24 (depends on 9)

The camera of claim 9 wherein the second set of photodetectors detects red, green, blue, or infra-red (IR) light.

### Claim 25 (depends on 16)

The image sensor of claim 16 wherein the second set of photodetectors detects red, green, blue, or infra-red (IR) light.