STRAIN AND MOSAIC SPREAD OF CARBON AND GALLIUM CO-IMPLANTED GAAS

The strain and crystalline perfection of GaAs implanted with either carbon, gallium, or both carbon and gallium ions (5 X 10(14) cm-2) were investigated using high-resolution triple axis diffractometry. We determined that a significant amount of carbon occupied substitutional sites after rapid thermal annealing only when gallium was co-implanted. The carbon in the carbon-implanted layer remained in nonsubstitutional sites after annealing. In both cases, most of the lattice strain in the implanted layer decreases upon annealing, but a defective crystalline structure with an extensive mosaic spread evolves. Conventional double-axis x-ray measurements were employed for comparison.