# US 4,397,695 A · Method for stabilizing the current gain of NPN -silicon transistors

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,397,695 A
- Document ID: US4397695A
- Status: Granted
- Kind: A
- Application number: 06/269,740
- Filed: 1981-06-02
- Granted: 1983-08-09
- Earliest claimed: 1980-06-04
- Assignees: Siemens Aktiengesellschaft
- Inventors: Manfred Arlt; Joachim Dathe
- Web page: https://patentgrep.com/patent/US4397695A

## CPC

- H10P 95/90: Thermal treatments, e.g. annealing or sintering
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Stabilizing the current gain of NPN-silicon transistors by two annealing processes: a high temperature annealing process for at least 30 minutes at a temperature of 510.degree. to 590.degree. C., and a lower temperature annealing process for at least 30 minutes at a temperature of 380.degree. to 460.degree. C.

## Claims

### Claim 1

Method for stabilizing the current gain of NPN-silicon transistors after high-temperature processes necessary for manufacturing the transistors have been completed, comprising first annealing the transistors for at least 30 minutes at a temperature of 510.degree. to 590.degree. C. and then for at least 30 minutes at a temperature of 380.degree. to 460.degree. C.

### Claim 2 (depends on 1)

Method according to claim 1, wherein the annealing process at the higher temperature is carried out at 530.degree. to 570.degree. C.

### Claim 3 (depends on 1)

Method according to claim 1, wherein the annealing process at the higher temperature is carried out for at least 60 minutes.

### Claim 4 (depends on 1)

Method according to claim 1, wherein the annealing process at the lower temperature is carried out at 420.degree. to 450.degree. C.

### Claim 5 (depends on 1)

Method according to claim 1, wherein the annealing process at the lower temperature is carried out for at least two hours.

### Claim 6 (depends on 1)

Method according to claim 1, wherein at least one annealing process is carried out in a nitrogen-hydrogen atmosphere.

### Claim 7 (depends on 2)

Method according to claim 2, wherein the annealing process at the higher temperature is carried out for at least 60 minutes.

### Claim 8 (depends on 2)

Method according to claim 2, wherein the annealing process at the lower temperature is carried out at 420.degree. to 450.degree. C.

### Claim 9 (depends on 3)

Method according to claim 3, wherein the annealing process at the lower temperature is carried out at 420.degree. to 450.degree. C.

### Claim 10 (depends on 7)

Method according to claim 7, wherein the annealing process at the lower temperature is carried out at 420.degree. to 450.degree. C.

### Claim 11 (depends on 3)

Method according to claim 3, wherein the annealing process at the lower temperature is carried out for at least two hours.

### Claim 12 (depends on 4)

Method according to claim 4, wherein the annealing process at the lower temperature is carried out for at least two hours.

### Claim 13 (depends on 1, 3, 4, 5)

Method according to claim 1 or claim 3 or claim 4 or claim 5, wherein the annealing process at the higher temperature is carried out prior to effecting a metallization of the transistors by sintering, and the annealing process at the lower temperature is carried after or simultaneously with, the metallization sintering of the transistors.