Physics based models for process optimization

Abstract

The shrinking of Si device dimensions has revealed the need of detailed atomistic models to gain better understanding of physical mechanisms involved in device fabrication as a way for process optimization. Our atomistic model for amorphization based on the accumulation of bond defects captures the sensitivity of defect accumulation to implant parameters, such as wafer temperature or flux. These parameters affect the width of amorphous layers formed by ion implantation and, as a result, the residual damage that remains beyond the amorphous/crystalline interface after solid phase epitaxial regrowth at low temperature. During additional higher temperature anneals, Si interstitials from the end of range are injected and cause B deactivation through the growth of preexisting B clusters in the regrown amorphous layer. The presence of impurities, such as F or C acting as Si interstitial traps, may prevent Si interstitials from reaching B atoms, and thus, the undesirable enhanced B diffusion and deactivation.