Hydrogen Concentration and Bond Configurations in Silicon Nitride Films Prepared by ECR Plasma CVD Method

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Abstract
The influence of deposition conditions on the hydrogen concentration and bond configurations in silicon nitride (SiN) films prepared by the electron cyclotron resonance plasma CVD(ECR P-CVD) method has been studied in comparison with those prepared by a conventional plasma CVD(P-CVD) method, by means of secondary ion mass spectrometry (SIMS), infrared absorption (IR) spectra and electron spin resonance (ESR). SiN films deposited at low microwave powers and a relatively high SiH4 flow rate had higher H concentrations than those deposited at high microwave powers. The hydrogen concentration was found to be in the range from 1.3×1022-5×1021/cm3 (13.8-4.7%) at microwave powers between 50 and 500 W. The bond configurations in the films are markedly dependent upon the deposition conditions. SiN films with only N-H bonds are thermally stable, even after annealing at 900°C in a dry N2 atmosphere, while almost all the H atoms are lost after annealing for films with both N-N and Si-H bonds. Annealing studies by ESR measurements revealed that the H concentration in the films has little influence on the spin density.