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

The effects of the gas-Bow-rate ratio on the electrical characteristics and the Fowler-Nordheim (FN) current stress resistance were investigated for S i oxynitride grown with helicon-wave excited (HWP) N-2-Ar plasma. The Bow-r ate 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 oxy nitride (probably Si2N2O) was formed through the entire film thickness when the N-2 gas-Bow-rate ratio was 100% (N-2 only), though a small amount of S i suboxide was included. The capacitance-voltage (C-V) measurements reveale d that the interface-state density was the lowest in this Row-rate ratio ca se, as the grown layer was postannealed at moderate temperatures (300-500 d egrees C). Fowler-Nordheim current injection was performed using the metal/ Si-oxynitride/Si capacitors thus fabricated. The shift of the threshold vol tage was the lowest for the sample grown without Ar mixing. It was smaller than that for the thermal Si oxide (SiO2) grown at 900 degrees C. The resul ts of FN current stress resistance experiments were explained in terms of t he surface plasmon and avalanche breakdown models.