Rapid plasma hydrogenation process for polysilicon MOSFETs

• US 5,250,444 A
• Filed: 02/21/1992
• Issued: 10/05/1993
• Est. Priority Date: 02/21/1992
• Status: Expired due to Fees

• Current Assignee: North American Philips Corp. (Koninklijke Philips N.V.)
• Original Assignee: North American Philips Corp. (Koninklijke Philips N.V.)
• Inventors: Mitra, Uday, Rossi, Barbara A., Khan, Babar
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): CHAUDHARI, CHANDRA P
• Application Number:
  US07/842,854
• Time in Patent Office: 592 Days
• Field of Search: 437/21, 437/24, 437/25, 437/41, 437/247, 437/248, 437/937, 148/DIG. 125, 148/DIG. 128, 148/DIG. 157
• US Class Current: 438/162
• CPC Class Codes: H01L 21/3003 Hydrogenation or deuterisation, e.g. using atomic hydrogen from a plasma
• CPC Class Codes: Y10S 148/128 Proton bombardment of silicon

Abstract

A method for rapid plasma hydrogenation of semiconductor devices is provided in which the hydrogenation is conducted in two steps, the first step being conducted at a hydrogenation temperature that is higher than the out-diffusion temperature at which a substantial amount of hydrogen diffuses out of said semiconductor device; and in the second step, the semiconductor device is cooled to a temperature at which out-diffusion is substantially avoided while the hydrogenation plasma is maintained.

Claims

1. A method of manufacturing a semiconductor device which comprises the steps of

(a) providing a semiconductor body capable of undergoing hydrogen in-diffusion and hydrogen out-diffusion at selected temperatures;

(b) subjecting said semiconductor body to plasma hydrogenation to effect in-diffusion of atomic hydrogen, said in-diffusion being effected at a hydrogenation temperature that is higher than the out-diffusion temperature at which a substantial amount of hydrogen escapes from said semiconductor body; and

(c) maintaining said hydrogenation plasma while said semiconductor body is cooled to a temperature at which out-diffusion is substantially avoided.

5. A method as claimed in claim 1 wherein said semiconductor device is a polysilicon liquid crystal display device.

6. A method as claimed in claim 1 wherein said semiconductor device is a polysilicon thin film transistor.

2. A method of manufacturing a semiconductor device which comprises the steps of

(a) providing a semiconductor body capable of undergoing hydrogen in-diffusion and hydrogen out-diffusion at selected temperatures;

(b) subjecting said semiconductor body to plasma hydrogenation to effect in-diffusion of atomic hydrogen, said in-diffusion being effected at a hydrogenation temperature that is higher than the out-diffusion temperature at which a substantial amount of hydrogen escapes from said semiconductor body;

(c) maintaining said hydrogenation plasma at said hydrogenation temperature for a period of time sufficient to obtain substantial equilibrium of said hydrogen in-diffusion and out-diffusion relative to said semiconductor body; and

(d) maintaining said semiconductor body in contact with said hydrogenation plasma while said semiconductor body is cooled to a temperature at which out-diffusion is substantially avoided.

3. A method of manufacturing a semiconductor device which comprises the steps of

(a) providing a semiconductor body capable of undergoing hydrogen in-diffusion and hydrogen out-diffusion at selected temperatures;

(b) subjecting said semiconductor body to a hydrogenation plasma to effect in-diffusion of atomic hydrogen, said in-diffusion being effected at a temperature within the range of about 400°

C. to about 800°

C.; and

(c) maintaining said semiconductor body in contact with said hydrogenation plasma while said semiconductor body is cooled to a temperature within the range of about 25°

C. to about 375°

C.

4. A method of manufacturing a semiconductor device which comprises the steps of

(a) providing a semiconductor body capable of undergoing hydrogen in-diffusion and hydrogen out-diffusion at selected temperatures;

(b) subjecting said semiconductor body to a hydrogenation plasma to effect in-diffusion of atomic hydrogen, said in-diffusion being effected at a temperature of about 435°

C. for a period of time not greater than about 30 minutes; and

(c) maintaining said semiconductor body in contact with said hydrogenation plasma while said semiconductor body is cooled a temperature of about 325°

C. over a period not greater than about 30 minutes.

7. A method as claimed in claim 4 in which said semiconductor device is a polysilicon liquid crystal display device.

8. A method as claimed in claim 4 wherein said semiconductor device is a polysilicon thin film transistor.

9. A method as claimed in claim 4 wherein said semiconductor device is a polysilicon MOSFET.