Optimisation of PECVD poly-SiGe layers for MEMS post-processing on top of CMOS

Poly-SiGe offers an attractive alternative for low temperature MEMS postprocessing above CMOS. This paper illustrates this fact through several investigations made to obtain a material with excellent mechanical properties (low stress, low stress gradient), and electrical properties (low resistivity) for different structural layer thicknesses and deposition techniques. It was also established that these layers are stable with time and temperature variation, thus ensuring long-term stability in the performance of poly-SiGe based MEMS devices.