线性微波化学气相沉积制备SiNx薄膜的微结构及光学性能研究

利用自主研发的线性微波化学气相沉积系统在不同微波功率、微波占空比、基片温度、特气比例条件下制备了SiN_x薄膜. 通过扫描电子显微镜、椭圆偏振仪等表征测量技术, 研究了不同工艺参数对SiN_x薄膜表面形貌、元素配比、折射率、沉积速度的影响, 并探讨了薄膜元素配比、折射率、沉积速度间的关系. 结果表明: 利用线性微波沉积技术, 不同工艺参数下制备的SiN_x薄膜组成元素分布均匀, 同时具有平整的表面状态; 特气比例和微波占空比是影响薄膜折射率的最主要因素, 薄膜折射率在1.92–2.33之间连续可调; 微波功率、微波占空比、沉积温度、特气比例都对SiN_x 薄膜沉积速度影响较大, 制备的SiN_x薄膜最大沉积速度为135 nm·min^-1.

The microstructure and optical properties of SiNx deposited by linear microwave chemical vapor deposition

SiN_x films are synthesized on Si substrates in a home-made linear microwave plasma enhanced chemical vapor deposition system at different microwave powers, duty cycles, substrate temperatures, and ratios of silane (SiH₄) flow to ammonia (NH₃) gas flow. The effects of technological parameters on morphology of film surface, stoichiometric proportion, refractive index and deposition rate of SiN_x film are characterized by scanning electron microscopy (SEM) and elliptical polarization instrument, and the relationships among stoichiometric proportion, refractive index and deposition rate are investigated. The results from SEM analysis indicate that the surfaces are smooth and the elements are homogeneously distributed in the films obtained under different deposition parameters. The ratio of SiH₄ flow to NH₃ gas flow and the duty cycle are the most critical factors determining the refractive index which can be changed from 1.92 to 2.33. The thickness measurements show that the deposition rate of SiN_x film is affected by microwave power, duty cycle, substrate temperature and flow ratio. The maximum deposition rate achieved in the paper is 135 nm·min^-1.