Effects of Gas-Flow-Rate Ratio on Electrical Characteristics and Fowler-Nordheim Stress Resistance of Si Oxynitride Grown with Helicon-Wave-Excited N 2 –Ar plasma

• Published in: Japanese Journal of Applied Physics Vol. 39; no. 3R; p. 1013
• Main Authors: Fumihito Oka, Fumihito Oka, Masayuki Tachikawa, Masayuki Tachikawa, Tatsuaki Tsukuda, Tatsuaki Tsukuda, Hideaki Ikoma, Hideaki Ikoma
• Format: Journal Article
• Language: English
• Published: 01.03.2000
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.39.1013

The effects of the gas-flow-rate ratio on the electrical characteristics and the Fowler-Nordheim (FN) current stress resistance were investigated for Si oxynitride grown with helicon-wave excited (HWP) N 2 –Ar plasma. The flow-rate ratio of N 2 [N 2 /(N 2 +Ar)] was varied from 100% (N 2 only) to 60%. The X-ray photoelectron spectroscopic data (XPS) indicated that uniform Si oxynitride (probably Si 2 N 2 O) was formed through the entire film thickness when the N 2 gas-flow-rate ratio was 100% (N 2 only), though a small amount of Si suboxide was included. The capacitance–voltage ( C – V ) measurements revealed that the interface-state density was the lowest in this flow-rate ratio case, as the grown layer was postannealed at moderate temperatures (300–500°C). Fowler-Nordheim current injection was performed using the metal/Si-oxynitride/Si capacitors thus fabricated. The shift of the threshold voltage was the lowest for the sample grown without Ar mixing. It was smaller than that for the thermal Si oxide (SiO 2 ) grown at 900°C. The results of FN current stress resistance experiments were explained in terms of the surface plasmon and avalanche breakdown models.