Application of thin crystalline Si.sub.3 N.sub.4 liners in shallow trench isolation (STI) structures

US5747866A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Herbert L. Ho · New Windsor, US
• Erwin Hammerl · Stormville, US
• David M. Dobuzinsky · New Windsor, US
• Herbert Palm · Hohenkirchen, DE
• Stephen G. Fugardi · New Milford, US
• Atul Ajmera · Wappingers Falls, US
• James F. Moseman · Glenham, US
• Samuel C. Ramac · Beacon, US

Key dates

• Filing date: Jan 21, 1997
• Grant date: May 5, 1998
• Expiry date: Jan 21, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S148/05
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

Silicon integrated circuits use a crystalline layer of silicon nitride (Si.sub.3 N.sub.4) in shallow trench isolation (STI) structures as an O.sub.2 -barrier film. The crystalline Si.sub.3 N.sub.4 lowers the density of electron traps as compared with as-deposited, amorphous Si.sub.3 N.sub.4. Further, a larger range of low-pressure chemical-vapor deposited (LPCVD) Si.sub.3 N.sub.4 films can be deposited, providing a larger processing window for thickness controllability. An LPCVD-Si.sub.3 N.sub.4 film is deposited at temperatures of 720.degree. C. to 780.degree. C. The deposited film is in an amorphous state. Subsequently, a high-temperatures rapid-thermal anneal in pure nitrogen or ammonia is conducted at 1050.degree. C. to 1100.degree. for 60 seconds.