nc-Si:H薄膜的内应力特性研究

Study on intrinsic stress of nc-Si:H film

测试了采用PECVD生长的氢化纳米硅(nc-Si:H)薄膜的内应力。利用XRD、Raman、AFM、HRTEM研究了nc-Si:H薄膜的微结构,用全场薄膜应力测试仪测量了nc-Si:H薄膜的内应力。结果表明:nc-Si:H薄膜的内应力与薄膜的微结构密切相关,强烈依赖于制备工艺。压应力随掺杂浓度的提高而增加;在一定功率密度范围内掺磷nc-Si:H薄膜的压应力随功率密度增加而减少,并过渡为张应力;在373-523K之间,掺硼nc-Si:H薄膜的压应力随衬底温度升高而增加;nc-Si:H薄膜的压应力随氢气对硅烷稀释比的变化而变化。

Series of nc- Si:H films were prepared by using Plasma Enhanced Chemical Vapor Deposition (PECVD) system with RF(13.56MHz) and DC bias stimulating. The instrinsic stress of doped hydro- genated nano- crystalline silicon (nc- Si:H) film was measured entirely. Its microstructure was inves- tigated by using X- ray Diffraction (XRD), Raman Spectrum Meter, Atomic Force Microscope (AFM) and High Resolution Transmission Electron Microscope (HRTEM). The results show that the intrinsic stress is intensively dependent on the microstructure and varies with the depositing parameters of nc- Si:H films,i.e., the compressive stress increases with the increasing of the doping ratio(B2H6(PH3)/SiH4 vol% ) in both B- doped and P- doped nc- Si:H films. The compressive stress decreases with the increasing of the RF power density, and then changes into tensional stress within a certain range of RF power density. The compressive stress increases with the increasing of the substrate temperature between 373K and 523K. And the compressive stress alters with the variation of dilution ratio of H2 deleted SiH4 (SiH4/H2 vol% ).