Deposition of aluminium nitride films by electron cyclotron resonance plasma-enhanced chemical vapour depositon

An electron cyclotron resonance plasma source was used for the deposition of aluminium nitride (AlN). AlN films were grown using trimethyl aluminium in hydrogen as carrier gas and nitrogen or ammonia as a nitrogen source onto silicon, glass and steel substrates. The deposition temperature ranged from 200 to 600 deg C, the microwave power was varied from 250 to 400 W and the operation pressure was (1-4) x 10 exp -3 mbar. Atomic composition of the samples was investigated by Auger electron spectrometry and Fourier transform IR spectrometry and mechanical properties were investigated by a dynamic force-penetration method and scratch test. The influence of the deposition parameters on the structure and hardness were investigated. The incorporation of oxygen into the AlN films after the deposition is caused by diffusion of water along the grain boundaries of textured layers. Universal hardness of 10 000 N mm exp -2 and critical loads up to 42 N were found for AlN coatings on steel substrates.