SYNCHROTRON X-RAY TOPOGRAPHY AND MICRO-RAMAN SPECTROSCOPY OF BORON DOPED SILICON WAFER USING RAPID THERMAL DIFFUSION

摘要

In this paper we discuss the application of Synchrotron X-ray Topography (SXRT) and micro-Raman spectroscopy (μRS) to the investigation of stress introduced into silicon wafers during rapid thermal processing (RTP). SXRT, μRS and optical microscopy observations of wafers subjected to RTP are compared with theoretical predictions of stress distributions across the wafer. It has been shown that stress generation, and the corresponding formation of slip lines during rapid thermal diffusion (RTD), increases with the time spent at peak temperature (1050°C). The introduction of boron atoms into silicon increases the stress that is induced in the lattice. SXRT clearly shows a dense array of misfit dislocations that are formed in heavily doped silicon after prolonged RTD. These results were confirmed by micro-Raman spectroscopy. Surface strain was observed in wafers that were doped for 5 s at 1050°C, however, there was no evidence of any dislocations.