Outdiffusion of Be during rapid thermal annealing of high dose be implanted gaas

The outdiffusion of Be implanted into GaAs has been found to be identical after capless or capped (Si3N4 or Si02 ) rapid thermal annealing (RTA) at 900-1000 ºC and to depend on the Be dose and its proximity to the surface. The outdiffusion is more pronounced when the Be implant is shallow (< 0.1 p,m) andlor the Be + dose is high (> 1 X 1015 cm-²). It is demonstrated that the Be outdiffusion is driven by the presence of a highly damaged surface layer. Auger results suggest the formation of a BeOx compound at the surface of a high.dose (1 X 1016 cm-²) Be-implanted sample that underwent capless RTA at 1000 ºC/1 s. It appears that BeOx formation occurs when the outdiffused Be interacts with the native Gal As oxides during annealing. AU the Be remaining in the GaAs after a > 900 ºC/2s RTA is electrically active