Microstructural characterization of radio frequency magnetron sputter-deposited Ga2O3:Mn phosphor thin films

Ga2O3:Mn phosphor thin films have been prepared by radio frequency (rf) magnetron sputtering of a 2 mol % Mn-doped Ga2O3 target in an oxygen-argon mixture atmosphere. The deposition rate of the films decreased from 14 to 12 Angstrom/min when the working gas pressure decreased from 30 to 2 mTorr, while the O/Ga ratio of similar to1.5 did not systematically depend on the pressure. Films deposited at higher working gas pressure had a porous columnar structure containing a large void, typical of zone I growth, while films produced at lower pressure had relatively smooth surfaces with a dense structure, typical of zone T growth. The results obtained are consistent with energetic particle bombardment of the depositing films promoting surface adatom mobility at lower working gas pressure. Films deposited at working gas pressures greater than or equal to 15 mTorr showed a random orientation after a postdeposition anneal at 1000 degreesC. Below 15 mTorr, annealed films were strongly textured with the (111) and (020) planes parallel to the surface. (C) 2002 American Vacuum Society.