DEEP IMPLANTATION OF NITROGEN INTO GAAS FOR SELECTIVE 3-DIMENSIONAL MICROSTRUCTURING

Results are presented for deep implantation of nitrogen into n-type GaAs. The main purpose of these investigations is to clarify whether deep implantation can be a suitable process to create buried, selectively etchable layers for the fabrication of micromechanical structures in GaAs. The implanted layers have been characterized by x-ray photoelectron spectroscopy (XPS) combined with sputter profiling, electrical measurements using test Schottky diodes, and selected etching techniques. XPS depth profiling shows the formation of a GaAs1-xNy layer with y < x that can be etched with high selectivity with respect to the GaAs using alkaline agents. The degree of radiation damage introduced during implantation is determined by planar test diodes located at different depth levels in the implanted structure. It can be shown that implantation damage recovers to a certain extent after annealing at a temperature of about 750-degrees-C although the optimum annealing conditions have not yet been found.