Influence of temperature and of structure of antimony substrate on gallium diffusion into the GaSb semiconductor compound

Article abstract of DOI:10.1016/S0925-8388(00)01032-X

The diffusion coefficient of Ga electrodeposits on Sb electrodeposited thin films, either amorphous or crystalline, was investigated to determine the influence of the morphology and structure of the antimony substrates on the diffusion and reaction process. The Ga/Sb bilayer was studied by SEM-EDS and X-ray diffraction before and after heating at temperatures of 50, 75 and 100 °C. The formation of the GaSb semiconductor compound was particularly considered and the activation energy and frequency factor of the process was determined. At these temperatures, Ga was at least partially molten and the diffusion coefficient showed that the geometrical factor was prevailing over the structural one. For example, at 75 °C, the values of the diffusion coefficient were 1.5×10^-17 and 6.3×10^-17 m² s^-1 for the amorphous and crystalline antimony, respectively. On the contrary, at 20 °C, a temperature at which Ga is in the solid state, the structural factor prevailed over the geometrical one and values were obtained lower by around three orders of magnitude. The prevailing influence at 20 °C was identical to that previously observed for In diffusion into amorphous and crystalline Sb with InSb formation. The experimental results, both at low and high temperatures, are discussed also taking the behaviour of the In-Sb system into account.