Impact of Emissivity-Independent Temperature Control in Rapid Thermal Processing

Abstract

ABSTRACTDue to polycrystallization, the emissivity of amorphous silicon is known to vary during annealing at temperatures above 500°C. This transition from α-Si to poly-Si usually occurs during the ramp and the beginning of steady stages of the rapid thermal process. However, the majority of current temperature control methods in RTP neglect time-dependent change of emissivity, and the temperature profile of process calibration is different from that of real annealing process. Various kinds of wafers with in-situ doped amorphous Si are investigated using emissivity-independent temperature control. Some process parameters and material parameters, such as ramp rate and doping level, are explored to study their influences on emissivity change, and consequently on electrical and optical parameters.