# US 9,520,479 B1 · Low-temperature epitaxial method for manufacturing backside field stop layer of insulated gate bipolar transistor (IGBT)

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- Number: US 9,520,479 B1
- Document ID: US9520479B1
- Status: Granted
- Kind: B1
- Application number: 15/046,294
- Filed: 2016-02-17
- Granted: 2016-12-13
- Earliest claimed: 2015-11-30
- Assignees: Pfc Device Holdings Limited
- Applicants: PFC Device Holdings Limited
- Inventors: Mei-Ling Chen; Kuan-Yu Chen
- Web page: https://patentgrep.com/patent/US9520479B1

## CPC

- H10D 12/032: {of vertical IGBTs}
- H10D 62/60: Impurity distributions or concentrations
- H10D 12/441: {Vertical IGBTs}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A low-temperature epitaxial method manufactures backside field stop layer of insulated gate bipolar transistor (IGBT) first provides a first conductive type substrate and fabricates front-side elements and front metal layer on a front side of the IGBT. A second conductive type impurity layer is formed on a back side of the first conductive type substrate by low-temperature epitaxial process and a collector metal layer is formed on bottom face of the first conductive type substrate.

## Claims

### Claim 1

A low-temperature epitaxial method for manufacturing backside field stop layer of insulated gate bipolar transistor (IGBT), the method comprising:
(a) providing a first conductive type substrate and forming front side elements of IGBT and front side metal layer of IGBT on a front side of the first conductive type substrate;
(b) forming a plurality of first conductive type impurity layers on a back side of the first conductive type substrate by low-temperature epitaxial process;
(c) forming a second conductive type impurity layer on the back side of the first conductive type substrate by low-temperature epitaxial process; and
(d) forming a collector metal layer med on a bottom face of the first conductive type substrate,
wherein impurity concentrations of the first conductive type impurity layers formed in step (b) are decreased from a backside of the first conductive type substrate.

### Claim 2 (depends on 1)

The low-temperature epitaxial method in claim 1, wherein the low-temperature epitaxial process is plasma-enhanced chemical vapor deposition (PECVD) process.

### Claim 3 (depends on 1)

The low-temperature epitaxial method in claim 1, wherein the first conductive type is N type or P type.

### Claim 4 (depends on 1)

The low-temperature epitaxial method in claim 1, wherein four layers of first conductive type impurity layers are formed in step (b) to function as field stop layers.

### Claim 5 (depends on 1)

The low-temperature epitaxial method in claim 1, wherein a range of the impurity concentrations is between 1×1013 cm−3 and 1×1016 cm−3.

### Claim 6 (depends on 1)

The low-temperature epitaxial method in claim 1, wherein material of the collector metal layer is aluminum (Al), TiN or tungsten (W).