The growth kinetics of silicon nitride deposited from the SiH4-N2 reactant mixture in a remote plasma

The growth mechanism of silicon nitride (a-SiNx:H) from the SiH4–N2 reactant mixture is discussed on the basis of results obtained in a remote plasma. From the measured radical densities, it is concluded that ground-state N and SiH3 radicals dominate the a-SiNx:H growth process, as has been confirmed by the correlation between the N and SiH3 density in the plasma and the incorporation flux of N and Si atoms into the a-SiNx:H. From this correlation acceptable sticking probabilities for N and SiH3 (on the order of 0.01 and 0.1, respectively) are deduced while further support for the growth mechanism is given by the different temperature dependences of the Si and N incorporation flux. It is proposed that a-SiNx:H growth takes place by SiH3 radicals forming an a-Si:H-like surface layer that is simultaneously nitridated by the N radicals converting the surface layer into a-SiNx:H.