# US 6,635,950 B1 · Semiconductor device having buried boron and carbon regions, and method of manufacture thereof

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- Number: US 6,635,950 B1
- Document ID: US6635950B1
- Status: Granted
- Kind: B1
- Application number: 09/665,616
- Filed: 2000-09-19
- Granted: 2003-10-21
- Earliest claimed: 1997-02-26
- Assignees: Hitachi, Ltd.
- Inventors: Hidetsugu Ishida; Seiichi Isomae
- Web page: https://patentgrep.com/patent/US6635950B1

## CPC

- H10P 30/204: {into Group IV semiconductors}
- H10D 62/834: further characterised by the dopants
- H10P 30/208: {of electrically inactive species}
- H10P 30/224: {of a cluster, e.g. using a gas cluster ion beam}
- H10P 30/225: {of a molecular ion, e.g. decaborane}
- H10P 36/03: {within silicon bodies}
- H10D 62/832: being Group IV materials comprising two or more elements, e.g. SiGe
- Y10S 257/913: with means to absorb or localize unwanted impurities or defects from semiconductors, e.g. heavy metal gettering
- Y10S 257/914: Polysilicon containing oxygen, nitrogen, or carbon, e.g. sipos
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

To improve the gettering performance by ion implanting boron and improves the production yield of the semiconductor device by using an epitaxial wafer of good quality suppressing the occurrence of dislocations. For this purpose, an epitaxial wafer in which an epitaxial layer of about 1 μm is formed to a CZ semiconductor substrate implanted with boron ions which are dopant and carbon ions which are not a dopant is provided, and transistors are formed on the surface of the epitaxial layer.

## Claims

### Claim 1

A semiconductor device comprising:
a semiconductor substrate of a first conductivity type;
an epitaxial layer of a first conductivity type formed on the substrate, the epitaxial layer having a surface;
a well region of a conductivity type formed in the said epitaxial layer, said well region extending from the surface of the epitaxial layer to said substrate and having a surface; and
a gate insulating layer formed on the surface of said well region,
wherein the well region includes implanted boron impurities and implanted boron impurities, and wherein a depth of a peak concentration of said implanted boron impurities and a depth of a peak concentration of said implanted carbon impurities are substantially equal.

### Claim 2 (depends on 1)

A semiconductor device according to claim 1, further comprising a gettering layer on a rear surface of the semiconductor substrate.

### Claim 3 (depends on 1)

A semiconductor device according to claim 1, wherein the implanted carbon impurities are in a localized carbon region.

### Claim 4 (depends on 1)

A semiconductor device according to claim 1, wherein said well region extends into said semiconductor substrate.

### Claim 5 (depends on 1)

A semiconductor device according to claim 1, wherein the well region extends to a depth in a range of 1.5 to 4 μm from the surface of the epitaxial layer.

### Claim 6 (depends on 1)

A semiconductor device according to claim 1,
wherein the implanted carbon impurities were implanted in an amount of more than 1×1011 atoms.cm−2.

### Claim 7 (depends on 6)

A semiconductor device according to claim 6,
wherein the implanted carbon impurities were implanted in an amount of 1×1014 atoms.cm−2 to 1×1016 atoms.cm−2.

### Claim 8 (depends on 1)

A semiconductor device according to claim 1,
wherein the peak concentrations of said implanted boron impurities and said implanted carbon impurities are located in the semiconductor substrate.