a-SiN:H薄膜的对靶溅射沉积及微结构特性研究

采用对靶磁控反应溅射技术以N₂和H₂为反应气体在硅(100)和石英衬底上制备了氢化非晶氮化硅(a-SiN:H)薄膜. 利用台阶仪、原子力显微镜、紫外-可见(UV-VIS)光吸收和傅里叶红外透射光谱(FTIR)对薄膜沉积速率、微观结构及键合特性进行了分析. 结果表明, 利用等离子反应溅射可在较低衬底温度条件下(T_s<250℃)实现低表面粗糙度和高光学透过率的a-SiN:H薄膜制备. 增加衬底温度可使薄膜厚度减小, 薄膜光学带隙Eg提高, 薄膜无序度减小. FTIR分析结果表明, 薄膜主要以Si-N, Si-H和N-H键合结构存在, 随衬底温度增加, 薄膜中的键合氢含量减小, 而整体键密度和Si-N键密度增加. 该微观结构和光学特性的调整可归因衬底温度升高所引起的衬底表面原子迁移率和反应速率的增加.

Structural properties of hydrogenated amorphous silicon nitride films deposited by facing targets sputtering

Hydrogenated amorphous silicon nitride films were deposited on Si (100) and quartz substrate by facing targets sputtering (FTS) technique with N₂ and H₂ as reaction gas. The microstructure and bond configuration properties of films have been characterized by surface profilometer, atom force microscopy (AFM), ultraviolet-visible (UV-VIS) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The results indicate that low surface roughness and high optic transmissivity of the a-SiN:H films can be deposited under the substrate temperature (T_s) of 250°C by plasma reaction sputtering. The optical band gaps E_g and the degree of order of a-SiN:H films increases with increasing T_s. However, the thickness of samples is decreased with increasing T_s. The characterization of the a-SiN:H can be assigned to the Si-N stretching, Si-H stretching and N-H vibration modes by FTIR spectroscopy. Hydrogen concentration of the films decreases and Si-N bond density increases with increasing T_s. The change of bonding configuration and the decrease of disorder degree of the a-SiN:H films microstructure are attribute to the increase of surface mobility of atoms and the reaction rate with increasing T_s.