微机械悬桥法研究氮化硅薄膜力学性能

Investegation of mechanical property of LPCVD silicon nitride film with micromachined bridge

利用高精密纳米压入仪检测微机械悬桥的载荷-挠度曲线,来研究低应力LPCVD氮化硅薄膜的力学特性。通过大挠度理论分析,得到考虑了衬底变形对挠度有贡献的微桥挠度解析表达式。对于在加卸载过程中表现出完全弹性的微桥,利用最小二乘法对其挠度进行了拟合,从而得到杨氏模量、残余应力和弯曲强度等力学特性参数。低应力LPCVD氮化硅薄膜的研究结果:杨氏模量为(308.4±24.1)GPa,残余应力为(252.9±32.4)MPa,弯曲强度为(6.2±1.3)GPa。

The LPCVD silicon nitride microbridge in the elastic range was investigated using a wedge tip under the nanoindenter by the load-deflection curves of the bridge. Both the substrate deformation and the large deflection were considered in the model, and the Young's modulus was evaluated to be (308.4±24.1) GPa , with the residual stress of (252.9±32.4) MPa and the bending strength (6.2±1.3)GPa.