Stress and strain gradient control of polycrystalline SiC films

This work reports the development of very low residual stress and low strain gradient polycrystalline SiC (poly-SiC) thin films deposited by low pressure chemical vapor deposition (LPCVD). Using dichlorosilane (DCS, SiH 2 Cl 2 ) and acetylene (C 2 H 2 ) as precursors, it was found that the flow rate of DCS can be used to adjust the residual stress from tensile to compressive in as-deposited films. The resulting poly-SiC films, with tensile stresses lower than 50 MPa and strain gradients as low as 1.3×10 −4 °m −1 , are well-suited for MEMS and NEMS structural materials.