# US 2014/0191317 A1 · Rf ldmos device and method of forming the same

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- Number: US 2014/0191317 A1
- Document ID: US20140191317A1
- Status: Published application
- Kind: A1
- Application number: 14/147,484
- Filed: 2014-01-03
- Published: 2014-07-10
- Earliest claimed: 2013-01-06
- Assignees: Shanghai Huahong Grace Semiconductor Manufacturing Corporation
- Applicants: Shanghai Huahong Grace Semiconductor Manufacturing Corporation
- Inventors: Wensheng Qian
- Web page: https://patentgrep.com/patent/US20140191317A1

## CPC

- H10D 30/65: Lateral DMOS [LDMOS] FETs
- H10D 30/0221: {having asymmetry in the channel direction, e.g. lateral high-voltage MISFETs having drain offset region or extended-drain MOSFETs [EDMOS]}
- H10D 30/0281: {of lateral DMOS [LDMOS] FETs}
- H10D 30/603: {having asymmetry in the channel direction, e.g. lateral high-voltage MISFETs having drain offset region or extended drain IGFETs [EDMOS]}
- H10D 62/235: {of IGFETs (IGFETs having buried channels H10D30/637)}
- H10D 62/371: {Inactive supplementary semiconductor regions, e.g. for preventing punch-through, improving capacity effect or leakage current}
- H10P 30/20: into semiconductor materials, e.g. for doping
- H10D 62/109: {Reduced surface field [RESURF] PN junction structures}
- H10D 62/111: {Multiple RESURF structures, e.g. double RESURF or 3D-RESURF structures}
- H10D 64/111: {Field plates}
- 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

An RF LDMOS device is disclosed, including: a substrate having a first conductivity type; a channel doped region having the first conductivity type and a drift region having a second conductivity type, each in an upper portion of the substrate, the channel doped region having a first end in lateral contact with a first end of the drift region; a first well having the first conductivity type in the substrate, the first well having a top portion in contact with both of a bottom of the first end of the channel doped region and a bottom of the first end of the drift region; and a second well having the first conductivity type in the substrate, the second well having a top portion in contact with a bottom of a second end of the drift region. A method of forming such an RF LDMOS device is also disclosed.

## Claims

### Claim 1

A radio frequency (RF) laterally diffused metal oxide semiconductor (LDMOS) device comprising:
a substrate having a first conductivity type;
a channel doped region having the first conductivity type and a drift region having a second conductivity type, each in an upper portion of the substrate, the channel doped region having a first end in lateral contact with a first end of the drift region;
a first well having the first conductivity type in the substrate, the first well having a top portion in contact with both of a bottom of the first end of the channel doped region and a bottom of the first end of the drift region; and
a second well having the first conductivity type in the substrate, the second well having a top portion in contact with a bottom of a second end of the drift region.

### Claim 2 (depends on 1)

The RF LDMOS device of claim 1, wherein the top portion of the first well is spaced greater than 0.5 μm from top surfaces of the channel doped region and the drift region.

### Claim 3 (depends on 1)

The RF LDMOS device of claim 1, wherein the top portion of the second well is spaced greater than 0.5 μm from a top surface of the drift region.

### Claim 4 (depends on 1)

The RF LDMOS device of claim 1, wherein the first conductivity type is p-type and the second conductivity type is n-type.

### Claim 5 (depends on 1)

The RF LDMOS device of claim 1, wherein the first conductivity type is n-type and the second conductivity type is p-type.

### Claim 6

A method of forming a radio frequency (RF) laterally diffused metal oxide semiconductor (LDMOS) device, comprising:
providing a substrate having a first conductivity type;
forming a channel doped region having the first conductivity type and a drift region having a second conductivity type, each in an upper portion of the substrate, and a first well having the first conductivity type and a second well having the first conductivity type, both in the substrate, such that: the channel doped region has a first end in lateral contact with a first end of the drift region; the first well has a top portion in contact with both of a bottom of the first end of the channel doped region and a bottom of the first end of the drift region; and the second well has a top portion in contact with a bottom of a second end of the drift region.

### Claim 7 (depends on 6)

The method of claim 6, wherein forming a channel doped region having the first conductivity type and a drift region having a second conductivity type, each in an upper portion of the substrate, and a first well having the first conductivity type and a second well having the first conductivity type, both in the substrate includes the steps of:
forming a drift region having a second conductivity type in an upper portion of the substrate;
forming a first well having the first conductivity type at a bottom of a first end of the drift region and forming a second well having the first conductivity type at a bottom of a second end of the drift region; and
forming a channel doped region having the first conductivity type above the first well, the channel doped region having a first end in contact with the first end of the drift region and a bottom in contact with a portion of the top portion of the first well.

### Claim 8 (depends on 7)

The method of claim 7, wherein the first and second wells are each formed by an ion implantation process.

### Claim 9 (depends on 8)

The method of claim 8, wherein the ion implantation process includes one or more ion implantation steps.

### Claim 10 (depends on 9)

The method of claim 9, wherein one or more ion implantation steps have a total ion dose of 1×1012 atoms/cm2 to 1×1013 atoms/cm2.

### Claim 11 (depends on 7)

The method of claim 7, wherein the channel doped region is formed by a tilted ion implantation process.

### Claim 12 (depends on 6)

The method of claim 6, wherein the first conductivity type is p-type and the second conductivity type is n-type.

### Claim 13 (depends on 6)

The method of claim 6, wherein the first conductivity type is n-type and the second conductivity type is p-type.