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氮化硅(SiNx∶H)薄膜通常用作微测辐射热计焦平面阵列的支撑层、绝缘或隔热层。通过射频等离子体增强化学气相沉积(PECVD)制备了富硅型(0.80≤x≤1.16)氮化硅薄膜,利用X射线光电子能谱(XPS)和傅里叶红外透射光谱(FTIR)分析了薄膜的微观结构。发现薄膜内部保存了Si3N4基本结构单元,除此之外,波数位于790,820和950 cm-1的Si-N键的伸缩振动峰分别对应为Si3-Si-N,N2-Si-H2,及H-Si-N3结构单元;运用曲率方法测量了不同硅烷(SiH4)流量条件下制备的氮化硅薄膜样品的残余应力,发现薄膜应力一般表现为张应力,但随着硅烷流量的增大,薄膜的张应力减小。理论分析发现,H-Si-N3结构单元使薄膜呈现张应力,而Si3-Si-N结构单元以及Si-Si键相对地表现为压应力。因此,通过优化制备工艺,获取理想的薄膜微观结构,能更理性地调控薄膜的残余应力。
Silicon nitride (SiNx: H) films are commonly used as support, insulation or thermal insulation layers for the micro-bolometer array. Silicon-rich (0.80≤x≤1.16) silicon nitride films were prepared by radio-frequency plasma-enhanced chemical vapor deposition (PECVD). X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) The microstructure. In addition, the stretching vibration peaks of Si-N bonds with wave numbers of 790, 820 and 950 cm-1 correspond to Si3-Si-N, N2-Si-H2 and H- Si-N3 structural unit. The residual stress of silicon nitride films prepared under different silane (SiH4) flow rates was measured by curvature method. It was found that the film stress was generally tensile stress. However, with the increase of silane flow rate, Tensile stress decreases. The theoretical analysis shows that the H-Si-N3 structural unit makes the film tensile stress, while the Si3-Si-N structural unit and the Si-Si bond relatively show compressive stress. Therefore, by optimizing the preparation process and obtaining the ideal film microstructure, the residual stress of the film can be regulated more rationally.