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

X-Ray diffraction and atomic force microscopy structural properties investi gations of TiB2/GaAs device structures as-produced and annealed have been c arried out. The samples were obtained by magnetron sputtering on Czochralsk i-grown (001) GaAs substrates doped by Te up to a concentration of 10(18) c m(-3). The magnetron sputtering was carried out in an argon atmosphere at p ressure 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. Th e short-term annealing of the samples was carried out in a stream of hydrog en in the furnace at temperatures 400, 600 and 800 degreesC during 1 min wi th a heating velocity of 1800 degreesC/min. The TiB2-film thickness and mag netron sputtering current determined the grain size and surface roughness a s well as interface structural parameters. At sputtering current 0.4 A, som e process of film texturing takes place. The residual strains in the film i ncrease with a rise in the sputtering current. The structural relaxation at annealing is exhibited in decreasing of residual strains as well as film r ecrystallization and transformation of surface morphology. The dependence o f these processes on annealing temperature does not have monotonous charact er and differs for various thicknesses of TiB2-film. (C) 2000 Elsevier Scie nce S.A. All rights reserved.