# US 9,437,640 B2 · Engineering induced tunable electrostatic effect

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- Number: US 9,437,640 B2
- Document ID: US9437640B2
- Status: Granted
- Kind: B2
- Application number: 14/481,038
- Filed: 2014-09-09
- Published: 2015-03-12
- Granted: 2016-09-06
- Earliest claimed: 2013-09-09
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Sherry Mings; Patricia M. Liu; Steven C. H. Hung
- Web page: https://patentgrep.com/patent/US9437640B2

## CPC

- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/014: {of CMOS image sensors}
- H10F 39/199: {Back-illuminated image sensors}
- H10F 39/805: {Coatings}
- H10F 39/8053: {Colour filters}
- H10F 39/806: {Optical elements or arrangements associated with the image sensors}
- H10F 39/8063: {Microlenses}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

Backside illuminated sensors and methods of manufacture are described. Specifically, a backside illuminated sensor with a dipole modulating layer near the photodiode is described.

## Claims

### Claim 1

A method of forming a device, the method comprising:
forming a photodiode on a surface adjacent to and in electrical communication with a gate electrode, the photodiode formed in an insulating layer on the surface;
forming an oxide layer having a thickness on the insulating layer; and
depositing an insulator having a thickness on the oxide layer, the insulator comprising a dipole modulating layer having a thickness greater than about 10 Å and a fixed charge layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the dipole modulating layer is formed between and contacts both of the oxide layer and the fixed charge layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the fixed charge layer is formed between and contacts both the oxide layer and the dipole modulating layer.

### Claim 4 (depends on 1)

The method of claim 1, wherein the insulator comprises two fixed charge sub-layers, a first fixed charge sub-layer and a second fixed charge sub-layer.

### Claim 5 (depends on 4)

The method of claim 4, wherein the first fixed charge sub-layer contacts the oxide layer and the dipole modulating layer is positioned between the two fixed charge sub-layers.

### Claim 6 (depends on 5)

The method of claim 5, wherein the first fixed charge sub-layer has a thickness in the range of about 1 Å to about 100 Å.

### Claim 7 (depends on 5)

The method of claim 5, wherein the first fixed charge sub-layer has a thickness in the range about 1% to about 90% of a total thickness of the insulator.

### Claim 8 (depends on 5)

The method of claim 5, wherein the dipole modulating layer is spaced from the oxide layer by a distance in the range of about 1 Å to about 90 Å.

### Claim 9 (depends on 1)

The method of claim 1, wherein the thickness of the insulator is less than about 150 Å.

### Claim 10 (depends on 1)

The method of claim 1, wherein the dipole modulating layer and the fixed charge layer are present in a ratio in the range of about 1:100 to about 100:1.

### Claim 11 (depends on 1)

The method of claim 1, wherein the dipole modulating layer has a thickness in the range of about 1 Å to about 90 Å.

### Claim 12 (depends on 1)

The method of claim 1, further comprising forming an antireflective coating on the insulator.

### Claim 13 (depends on 12)

The method of claim 12, further comprising positioning a color filter over the insulator.

### Claim 14 (depends on 13)

The method of claim 13, further comprising positioning a lens over the color filter.

### Claim 15

A backside illuminated sensor comprising:
a substrate with a gate electrode thereon;
a photodiode in an insulating layer, the photodiode in electrical communication with the gate electrode, the insulating layer having a top above a top of the photodiode;
an oxide layer having a thickness up to about 30 Å on the insulating layer; and
an insulator above the oxide layer, the insulator comprising a dipole modulating layer and a fixed charge layer.

### Claim 16 (depends on 15)

The sensor of claim 15, wherein the fixed charge layer comprises a first fixed charge sub-layer and a second fixed charge sub-layer and the dipole modulating layer is between the first fixed charge sub-layer and the second fixed charge sub-layer.

### Claim 17 (depends on 15)

The sensor of claim 15, further comprising an antireflective coating over the insulator.

### Claim 18 (depends on 17)

The sensor of claim 17, further comprising a color filter and a lens positioned over the antireflective coating to direct light toward the photodiode.

### Claim 19 (depends on 15)

The sensor of claim 15, wherein the insulator has a thickness less than about 150 Å.

### Claim 20

A backside illuminated sensor comprising:
a substrate with a gate electrode thereon;
an insulating layer having a top on the gate electrode;
a photodiode having a top formed in the insulating layer and in electrical communication with the gate electrode, the top of the insulating layer being above the top of the photodiode;
an oxide layer at the insulating layer;
an insulator having a thickness less than about 150 Å above the oxide layer, the insulator comprising a dipole modulating layer and a fixed charge layer, the fixed charge layer comprising a first fixed charge sub-layer and a second fixed charge sub-layer and the dipole modulating layer is between the first fixed charge sub-layer and the second fixed charge sub-layer; and
an antireflective coating over the insulator; and
a color filter and a lens positioned over the antireflective coating to direct light toward the photodiode.