Preparation of Aluminum Nitride Thin Films by CVD

Abstract

AlN films were prepared by CVD using aluminum halide (AlCl3) and aluminum alkyl ((CH3)3Al) precursors. The appropriate deposition conditions to obtain polycrystalline AlN films using A1C13 precursor were found at Tdep = 1173 K, Ptot = 66.6 Pa and N2/NH3 = 0.75. It was found that AlN films of different crystallinity can be obtained from (CH3)3Al precursor at Tde = 973-1023 K, Ptot = 1.99 kPa, only under a H2 atmosphere. AlN films can be grown highly oriented in the (210) direction on amorphous quartz substrates depending on their thicknesses. The 0.1 -0.2 μm thick AlN films were transparent and their refractive indexes were about 1.4-1.6.