Characterization of n-type regions in GaAs formed by silicon fluoride molecular ion implantations

Abstract

Implantations of silicon and silicon fluoride ions into semi-insulating GaAs wafers were performed to compare and evaluate the quality of the n-type layers that were produced. The use of SiFx (x=1,2,3) molecular ion implantations creates n-type active regions and n+ ohmic contact layers employing a higher implant energy than that needed to achieve a similar projected range for silicon ions. The higher energy allows the implanter to operate with a more stable and reproducible ion beam for shallow implant applications. Variables affecting the net electrically active ion distributions, such as the ion beam incidence angle, and the use of furnace or rapid thermal annealing cycles for implantation activation are addressed. Capacitance-voltage profiles were obtained for the n-type regions, and the free carrier distributions for the n+ implantations were obtained by polaron electrolytic profiling. The implanted regions were characterized by Hall-effect measurements, cathodoluminescence, and secondary ion mass spectroscopy.