Role of Ions and Radical Species in Silicon Nitride Deposition by ECR Plasma CVD Method

The growth kinetics of silicon nitride (SiN) films prepared by the electron cyclotron resonance (ECR) CVD method have been investigated. Studying both the compositional properties of films deposited by a shielding mask to a plasma stream just above the silicon wafer and optical emission spectrometry resulting from the discharge of SiH4/N2 mixture gas and N2 gas, it is deduced that N2 ions can directly contribute to the formation of SiN films. Although N2 radicals also can play a role in SiN formation, ion- assisted effects seem to be necessary for dense SiN formation.