Monolithic integration of MEMS devices with driving and controlling electronics is advantageous for improving performance and lowering cost. Polycrystalline silicon-germanium (poly-SiGe), which has mechanical and electrical properties similar to poly-Si, is a promising candidate for the structural-layer material of post-CMOS integration of MEMS because poly-SiGe can be deposited at much lower temperatures than poly-Si. While low-resistivity poly-SiGe can be easily obtained utilizing in-situ p-type (i.e. boron) doping during deposition, poly-SiGe films deposited at temperatures lower than 450°C generally exhibit some level of residual stress and strain gradient. The goal of this research is to reduce the stress and strain gradient in low-temperature deposited films without using any high temperature annealing.
Project end date: 08/22/03