Deposition and Passivation Properties of Plasma CVD AlN Films on GaAs using Metalorganic Al Source

Deposition conditions of plasma CVD AlN films were optimized, and the deposited films were examined as passivation films for the heat treatment of GaAs. It was found that when the AlN/GaAs was annealed at 850´C for 15 min. in H2 atmosphere, the film was more oxidized than when it was annealed in Ar atmosphere. Correponding to the oxidation, the surface carrier concentration is more decreased for the AlN/GaAs sample annealed in H2 atmosphere. Raman spectroscopy indicated that quite amount of stress was induced at the interface of AlN/GaAs when it was annealed in H2, and TO phonon which is inhibited on (100) surface was observed, When the AlN/GaAs was annealed in Ar atmosphere, the Raman peak shift due to the stress and the TO phonon was not observed, These results suggests that the PCVD-AlN is a good passivation film of GaAs when it is annealed in Ar atmosphere.