Rapid thermal annealing of gallium arsenide implanted with sulfur ions

Sulfur ions were implanted into semi-insulating GaAs. A SiO₂ film was deposited by either of two methods onto the implanted surface. The samples were then subjected to either rapid thermal annealing (using halogen lamps) for 10–12 s at 805°C or to conventional thermal annealing for 30 min at 800°C. The content of GaAs components in the film was determined from the spectra of Rutherford backscattering. The electron-concentration profiles were plotted using the measurements of the capacitance-voltage characteristics. It is shown that sulfur diffuses in two directions, i.e., towards the surface and into the GaAs bulk. The former process is stimulated by vacancies formed near the semiconductor surface during the deposition of SiO₂. The coefficients of the “volume” diffusion of S and of the diffusion of S towards the surface are two orders of magnitude larger upon rapid thermal annealing than upon conventional thermal annealing, with the degree of S activation also being higher.