Development of Crystallized Thick, Highly Doped a-Si:H Layers for Surface Micromachining of MEMS

Abstract:
This study presents the results of a process development of 14-20 micrometerm thick, and highly doped poly-silicon layers suitable for MEMS applications. Using plasma-enhanced chemical vapor deposition (PECVD) combined with annealing crystal-lization of the as-deposited thick a-Si:H films, the approach aims to fabricate blister-free, highly conductive, and low-stress polysilicon layers. By adjusting the doping gas flow rate and crystallization temperatures low layer stress and minimal stress gradients can be obtained. These advancements enhance the electrical conductivity and mechanical stability of future MEMS devices made from polysilicon.