Atomic layer deposition of Ga2O3 films from a dialkylamido-based precursor

The atomic layer deposition growth of Ga2O3 films was demonstrated using Ga-2(NMe2)(6) and water with substrate temperatures between 150 and 300 degrees C. At 250 degrees C, surface saturative growth was achieved with Ga-2(NMe2)(6) vapor pulse lengths of >= 1.5 s. The growth rate was 1.0 angstrom/cycle at substrate temperatures between 170 and 250 degrees C. Growth rates of 1.1 and 0.89 angstrom/cycle were observed at 150 and 275 degrees C, respectively. In a series of films deposited at 250 degrees C the film thicknesses varied linearly with the number of deposition cycles. Time-of-flight elastic recoil detection analyses demonstrated stoichiometric Ga2O3 films, with carbon, hydrogen, and nitrogen levels between 1 and 2.1, 4.8-5.4. and 0.6-0.9 at. %, respectively, at substrate temperatures of 170, 200, and 250 degrees C. The as-deposited films were amorphous, but crystallized to beta-Ga2O3 films upon annealing between 700 and 900 degrees C under a nitrogen atmosphere. Atomic force microscopy showed root-mean-square surface roughnesses of 0.4 and 0.6 nm for films deposited at 170 and 250 degrees C, respectively.