采用热丝化学气相沉积(HWCVD)方法沉积本征非晶硅薄膜,研究了热丝电流对薄膜结构及其钝化单晶硅片效果的影响。采用光谱型椭偏仪分析了非晶硅薄膜的介电常数虚部ε2和薄膜空位浓度的变化,采用傅里叶红外光谱测试仪分析了膜中Si—HX键,使用硅片的少子寿命表征钝化效果。结果表明:在热丝电流(两根直径为0.5 mm的钽丝的总电流)为20.5~23.5 A时,随着热丝电流增大薄膜中空位浓度逐渐增大,薄膜中氢总含量在热丝电流约22.0 A时出现峰值,而此时薄膜微观结构参数R*最小,钝化效果在约21.5 A处出现峰值,对应的表面复合速率低至2.9 cm/s。
The intrinsic The influence of the filament amorphous silicon thin film was prepared by hot-wire CVD (HWCVD). current on the structure and the passivation effect of the amorphous silicon thin films were studied. The imaginary part of dielectric constant (ε2) and the change of vacancy con- centration of the amorphous silicon thin films were Si-Hxbonds structure of the thi films were analyzed sivation effect was characterized by effective minority analyzed by spectroscopic ellipsometry (SE). The by fourier transform infrared spectrometer. The pas- carrier lifetime of the samples. The results show that in the filament current (the total current of the two tantalum filament, 0.5 mm of diameter) range of 20.5 - 23.5 A, the vacancy concentration of the thin films increases with the filament current increasing. The total hydrogen of amorphous silicon thin film reaches the maximum value and the microstructure parameters R* reaches the minimum value at about 22.0 A. The passivation effect shows a peak value at about 21.5 A, where the corresponding surface recombination velocity is below 2.9 cm/s.