Al2O3 thin films by plasma-enhanced chemical vapour deposition using trimethyl-amine alane (TMAA) as the Al precursor

We report the low temperature (200-300 degrees C) deposition of uniform, amorphous Al2O3 thin films by plasma-enhanced chemical vapour deposition (PECVD) using trimethyl-amine alane (TMAA) as the Al precursor. The thin films were deposited on both Si and quartz silica (SiO2) substrates. Deposition rates were typically 60 Angstrom min(-1) keeping the TMAA temperature constant at 45 degrees C. The deposited Al2O3 thin films were stoichiometric alumina with low carbon contamination (0.7-1.3 At%). The refractive index ranged from 1.54 to 1.62 depending on the deposition conditions. The deposition rate was studied as a function of both the RF power and the substrate temperature. The structure and the surface of the deposited Al2O3 thin films were studied using X-ray diffraction, atomic force microscopy (AFM) and scanning electron microscopy (SEM).