低压化学气相沉积制备低应力氮化硅膜的研究

A Study of Low-stress Silicon Nitride Films Prepared by Low Pressure Chemical Vapor Deposition

采用低压化学气相沉积方法,通过改变工艺气体配比,在硅衬底上生长低应力氮化硅薄膜。用应力仪、椭偏仪对生成的氮化硅薄膜的应力、生长速率、均匀性、折射率及腐蚀速率等进行实验。实验结果表明:低应力氮化硅薄膜制备的关键是增大DCS和NH3的配比,配比越大,生成的氮化硅薄膜应力越小,折射率越大,耐酸腐蚀能力越强,致密性越好;但随着配比增大,生成的氮化硅薄膜均匀性变差。选择合适的工艺气体配比可在硅衬底上制备出高质量的低应力氮化硅薄膜。

Low-pressure chemical vapor deposition is used to grow low-stress Si3N4 film on a silicon substrate by changing the process gas ratio.The stress,growth rate,uniformity,refractive index,and corrosion rate of the generated silicon nitride thin film are characterized by a stress meter and an ellipsometer.The experimental results show that the key to preparing low-stress silicon nitride films is to increase the ratio of DCS to ammonia.The larger the ratio,the smaller the film stress of silicon nitride generated by LPCVD,the larger the refractive index,the stronger the acid corrosion resistance,and the better the compactness.However,as the proportion increases,the uniformity of the resulting silicon nitride film becomes worse.Selecting the appropriate process ratio can produce high-quality low-stress silicon nitride film on silicon substrates.