# US 8,785,969 B2 · Resurf structure and LDMOS device

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- Number: US 8,785,969 B2
- Document ID: US8785969B2
- Status: Granted
- Kind: B2
- Application number: 13/169,052
- Filed: 2011-06-27
- Published: 2012-11-08
- Granted: 2014-07-22
- Earliest claimed: 2011-05-06
- Assignees: Episil Technologies Inc.
- Applicants: Chung-Yeh Lee; Pei-Hsun Wu; Shiang-Wen Huang
- Inventors: Chung-Yeh Lee; Pei-Hsun Wu; Shiang-Wen Huang
- Web page: https://patentgrep.com/patent/US8785969B2

## CPC

- H10D 84/151: {LDMOS having built-in components}
- H10D 30/0281: {of lateral DMOS [LDMOS] FETs}
- H10D 30/65: Lateral DMOS [LDMOS] FETs
- H10D 62/058: {by using trenches, e.g. implanting into sidewalls of trenches or refilling trenches}
- H10D 62/111: {Multiple RESURF structures, e.g. double RESURF or 3D-RESURF structures}
- H10D 62/115: {Dielectric isolations, e.g. air gaps}
- H10D 64/516: {the thicknesses being non-uniform}
- H10D 30/659: {having voltage-sensing or current-sensing structures, e.g. emulator sections or overcurrent sensing cells}
- H10D 62/127: {of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs}
- H10D 62/157: {Impurity concentrations or distributions}
- H10P 30/222: {characterised by the angle between the ion beam and the crystal planes or the main crystal surface (characterised by the angle between the ion beam and the mask H10P30/221)}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A reduced surface field (RESURF) structure and a lateral diffused metal oxide semiconductor (LDMOS) device including the same are provided. The RESURF structure includes a substrate of a first conductivity type, a deep well region of a second conductivity type, an isolation structure, at least one trench insulating structure, and at least one doped region of the first conductivity type. The deep well region is disposed in the substrate. The isolation structure is disposed on the substrate. The trench insulating structure is disposed in the deep well region below the isolation structure. The doped region is disposed in the deep well region and surrounds a sidewall and a bottom of the trench insulating structure.

## Claims

### Claim 1

A lateral diffused metal oxide semiconductor (LDMOS) device, comprising:
a substrate of a first conductivity type;
an epitaxial layer of a second conductivity type, disposed on the substrate;
a well region of the first conductivity type, disposed in the epitaxial layer;
a deep well region of the second conductivity type, disposed in the epitaxial layer;
a source region of the second conductivity type, disposed in the well region;
a drain region of the second conductivity type, disposed in the deep well region;
an isolation structure, disposed on the deep well region;
a gate, disposed on the epitaxial layer between the drain region and the source region and extending to above a portion of the isolation structure;
at least one trench insulating structure, disposed in the deep well region below the isolation structure; and
at least one doped region of the first conductivity type, disposed in the deep well region and surrounding a sidewall and a bottom of the trench insulating structure.

### Claim 2 (depends on 1)

The LDMOS device as claimed in claim 1, further comprising a buried layer of the second conductivity type disposed in the substrate below the deep well region.

### Claim 3 (depends on 2)

The LDMOS device as claimed in claim 2, wherein the doped region is physically connected to the isolation structure and the buried layer.

### Claim 4 (depends on 1)

The LDMOS device as claimed in claim 1, wherein the doped region is physically connected to the isolation structure and the substrate.

### Claim 5 (depends on 1)

The LDMOS device as claimed in claim 1, wherein a material of the trench insulating structure comprises silicon oxide.

### Claim 6 (depends on 1)

The LDMOS device as claimed in claim 1, wherein the isolation structure comprises a field oxide structure or a shallow trench isolation structure.

### Claim 7 (depends on 1)

The LDMOS device as claimed in claim 1, further comprising a body region of the first conductivity type disposed in the well region.

### Claim 8 (depends on 1)

The LDMOS device as claimed in claim 1, further comprising a gate oxide layer disposed between the gate and the epitaxial layer.

### Claim 9 (depends on 1)

The LDMOS device as claimed in claim 1, wherein the first conductivity type is P-type, and the second conductivity type is N-type; or the first conductivity type is N-type, and the second conductivity type is P-type.

### Claim 10

A reduced surface field (RESURF) structure, comprising:
a substrate of a first conductivity type;
an epitaxial layer of a second conductivity type, disposed on the substrate;
a deep well region of the second conductivity type, disposed in the epitaxial layer;
an isolation structure, disposed on the deep well region;
at least one trench insulating structure, disposed in the deep well region below the isolation structure; and
at least one doped region of the first conductivity type, disposed in the deep well region and surrounding a sidewall and a bottom of the trench insulating structure.

### Claim 11 (depends on 10)

The RESURF structure as claimed in claim 10, further comprising a buried layer of the second conductivity type disposed in the substrate below the deep well region.

### Claim 12 (depends on 11)

The RESURF structure as claimed in claim 11, wherein the doped region is physically connected to the isolation structure and the buried layer.

### Claim 13 (depends on 10)

The RESURF structure as claimed in claim 10, wherein the doped region is physically connected to the isolation structure and the substrate.

### Claim 14 (depends on 10)

The RESURF structure as claimed in claim 10, wherein a material of the trench insulating structure comprises silicon oxide.

### Claim 15 (depends on 10)

The RESURF structure as claimed in claim 10, wherein the isolation structure comprises a field oxide structure or a shallow trench isolation structure.

### Claim 16 (depends on 10)

The RESURF structure as claimed in claim 10, wherein the first conductivity type is P-type, and the second conductivity type is N-type; or the first conductivity type is N-type, and the second conductivity type is P-type.