Parallelogram-Shaped and Triangular Defects in GaAs

Abstract

Faulted triangular defects on the {111} planes, bounded along the h110i directions, are shown to develop after annealing in Be-implanted Si doped GaAs. These defects have not been reported for Be implantation studies using semi-insulating GaAs, and are thought to be planar Si precipitates. Similar defects have been reported by other workers near the highly compensated p-n junction region in diffused GaAs, and also in highly Si-doped GaAs. Prismatic parallelogram-shaped loops on the {110} planes, comprised of excess Ga and As interstitials created during implantation and bounded by perfect 90 dislocations along the h112i directions, are also identified in the implanted samples annealed at 500 C. These loops are replaced by triangular loops on the {110} planes in samples annealed at 600 C and higher. A model for the triangular loop formation, based on differing stabilities of the a-and b-type 90 dislocations, is proposed. To our knowledge, this is the first report of triangular loops on the {110} planes in GaAs.

Transmission Electron Microscopy of Be Implanted Si-Doped GaAs

“…These will be discussed in detail in another paper [15]. These were parallelogram-shaped loops in the samples annealed at 500 C and triangular-shaped loops in all the samples.…”