Evaporated aluminium nitride encapsulating films

Abstract AIN films were deposited onto GaAs and vitreous carbon substrates held at room temperature, by reactive evaporation of aluminium in the presence of nitrogen and/or NH 3 gas mixture. These films and their combination with very thin layers of Si 3 N 4 were successfully used as encapsulants for GaAs and were found to withstand annealing temperatures of up to 1100°C. Films grown by this novel method were analysed by Rutherford backscattering spectrometry and reflection high energy electron diffraction. Oxygen, nitrogen and aluminium were the only elements detected in the encapsulants. However, the best encapsulants were found to have the lowest oxygen content. The deposition conditions were found to be very important in preventing the reaction of the films with the surface of GaAs during heat treatment.