Silicon Nitride Films by Reactive Sputtering

Abstract

Silicon nitride films (from 500 to 7500Aå in thickness) have been deposited on silicon and silicon dioxide by reactive sputtering of a silicon cathode in a N2 glow discharge. Both d‐c and rf sputtering have been investigated. Physical and chemical properties of silicon nitride films prepared by sputtering were examined in reference to the process variables. The rate of deposition was approximately proportional to the square root of rf power density. Film density increased with power density, and decreased with gas pressure. Optimum gas pressure was in the range . Higher pressures resulted in less dense and electronically leaky films. Dielectric constant and etch rate in HF solution appeared to correlate well with film density. Residual pressure higher than was found to have a most detrimental effect. Argon and nitrogen gas mixtures resulted in excess silicon incorporation in the deposited nitride films.