X-ray, XTEM and RBS analysis of recrystallized ion beam amorphized CVD Si

Abstract

Ion beam modification of materials has been used for the formation of high quality single-crystal silicon (c-Si) over oxide, for high speed CMOS device applications. In the lateral solid phase epitaxy (LSPE) technique, thin c-Si layers (typically 300 nm) are formed by ion beam amorphization of a low pressure chemical vapor deposited (LPCVD) polysilicon layer over an oxidized Si wafer in which seed windows have been opened in the oxide. A c-Si layer is formed by LSPE from the single-crystal substrate up and over the thermal oxide adjacent to the oxide window for distances of up to 4 μm beyond the window boundary. We have obtained high quality 〈100〉 single-crystal silicon by conversion of polycrystalline LPCVD-Si, using rapid thermal annealing (RTA) followed by ion implantation amorphization and subsequent thermal recrystallization. Amorphization of LPCVD deposited poly-Si to a depth of 300 nm is achieved by LN 2 temperature implants of 5 × 10 14 cm −2 28Si + at 80 and 230 keV each. The crystallinity upon thermally induced recrystallization is evaluated by X-ray rocking curves, X-ray Read camera, RBS and cross-sectional transmission electron muscopy (XTEM).