IMPLANTATION-INDUCED DEFECTS IN HIGH-DOSE O-IMPLANTED SI

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 overl ayer, tensile strain (lattice contraction) results from a vacancy exce ss. The depth of the strain maximum is a function of the O ion dose. F or example, at low doses and an implant temperature of 150 degrees C, the strain increases from the surface to the amorphous/crystalline int erface, while at high doses, relaxation through dislocation formation is observed when the strain exceeds similar to 6400 ppm and thereafter the residual strain maximum moves toward the surface. The strain maxi mum before relaxation at a given O dose decreases as the implant tempe rature increases. This is due to dynamic annealing effects and is cons istent with thermally-activated dislocation nucleation and movement.