Implantation-induced defects in high-dose O-implanted Si

Abstract

Damage and strain in high-dose O-implanted Si have been systematically studied with Rutherford backscattering spectrometry, double crystal X-ray diffraction and transmission electron microscopy. In the Si overlayer, tensile strain (lattice contraction) results from a vacancy excess. The depth of the strain maximum is a function of the O ion dose. For example, at low doses and an implant temperature of 150°C, the strain increases from the surface to the amorphous/crystalline interface, while at high doses, relaxation through dislocation formation is observed when the strain exceeds ∼6400 ppm and thereafter the residual strain maximum moves toward the surface. The strain maximum before relaxation at a given O dose decreases as the implant temperature increases. This is due to dynamic annealing effects and is consistent with thermally-activated dislocation nucleation and movement.