SiH_4-NH_3-N_2体系LPCVD氮化硅薄膜的生长动力学

Growth Kinetics of SiNx Fim Based on SiH_4-NH_3-N_2 System Prepared by LPCVD

以硅烷和氨气分别作为低压化学气相沉积(LPCVD)氮化硅(SiNx)薄膜的硅源和氮源,以高纯氮气为载气,在热壁型管式反应炉中,借助椭圆偏振仪和原子力显微镜,系统考察了工作压力、反应温度、气体原料组成等因素对SiNx薄膜沉积速率和表面形貌的影响。结果表明:SiNx薄膜的生长速率随着工作压力的增大单调增加,随着原料气中氨气与硅烷的流量之比的增大单调减小。随着反应温度的升高,沉积速率逐渐增加,在840℃附近达到最大,随后迅速降低。在适当的工艺条件下,制备的SiNx薄膜均匀、平整。较低的薄膜沉积速率有助于提高薄膜的均匀性,降低薄膜的表面粗糙度。

SiNx film was grown on silicon wafer from SiH4-NH3-N2 system via low pressure chemical vapor deposition (LPCVD) in hot-wall horizontal tubular reactor. The growth rate and surface morphology of the film were investigated with the variation of deposition parameters, including total pressure, substrate temperature and source gas ratio, by spectroscopic ellipsometer and Atomic Force Microscope (AFM). The growth rate of the films increases with the increase of total pressure and decrease of NH3 to SiH4 ratio. As substrate temperature increases, growth rate linearly increases at lower temperature and then promptly decreases at higher temperature. AFM reveals that under appropriate deposition conditions, lower growth rate is helpful to improve the uniformity and surface roughness of SiNx film.