; Zhou, Chunlan
; Yu, Runsheng
; Wang, Baoyi
; Wei, Long] Chinese Acad Sci, Inst High Energy Phys, Key Lab Nucl Anal Tech, Beijing 100049, Peoples R China
; [Hao, Xiaopeng] Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China
Si-implanted thermal SiO2 layers and their annealing behaviour were investigated. In the results of variable-energy positron annihilation spectroscopy, the defects caused by ion implantation are manifested as a particularly low S parameter in the Si ion implantation region of the SiO2 layer. Compared with Fourier transform infrared measurements, it suggests that the decrease of the line shape S parameter after implantation is related to the compaction of implanted layers induced by the breaking of the SiO2 network structure. The presence of blue band emission (430-470 nm) in the implanted SiO2 layer is associated with neutral oxygen vacancy. An increase of the S parameter in the implanted layers is observed after annealing at different temperatures, but it is impossible completely recover the pre-implantation condition after a thermal treatment.