DAMAGE TO EPITAXIAL GAN LAYERS BY SILICON IMPLANTATION

Ion channeling and cross-sectional transmission electron microscopy we re used to study the extent and nature of Si ion implantation damage i n epitaxial GaN layers at liquid nitrogen temperature, Results indicat e that displacement damage produced by the implantation undergoes subs tantial dynamic annealing during implantation. As a result, at moderat e implantation doses residual implantation damage consists of a dense network of secondary defects, such as clusters and loops, which are a consequence of incomplete annihilation of implantation-produced defect s. Amorphous layers can be produced, bur the doses required are extrem ely high (> 10(16) cm(-2)) and amorphization appears to ''nucleate'' a t the surface. (C) 1996 American Institute of Physics.