The influence of TiB2-thin film thickness on metal-GaAs structural characteristics

X-Ray diffraction and atomic force microscopy structural properties investigations of TiB2/GaAs device structures as-produced and annealed have been carried out. The samples were obtained by magnetron sputtering on Czochralski-grown (001) GaAs substrates doped by Te up to a concentration of 10(18) cm(-3). The magnetron sputtering was carried out in an argon atmosphere at pressure in the chamber of 5 x 10(-3) torr. The currents of sputtering were 0.3 A and 0.4 A and the thickness of TiB2-films was from 10 nm to 50 nm. The short-term annealing of the samples was carried out in a stream of hydrogen in the furnace at temperatures 400, 600 and 800 degreesC during 1 min with a heating velocity of 1800 degreesC/min. The TiB2-film thickness and magnetron sputtering current determined the grain size and surface roughness as well as interface structural parameters. At sputtering current 0.4 A, some process of film texturing takes place. The residual strains in the film increase with a rise in the sputtering current. The structural relaxation at annealing is exhibited in decreasing of residual strains as well as film recrystallization and transformation of surface morphology. The dependence of these processes on annealing temperature does not have monotonous character and differs for various thicknesses of TiB2-film. (C) 2000 Elsevier Science S.A. All rights reserved.