VHF-PECVD法氢化微晶硅薄膜的低温制备

采用VHF-PECVD方法,以高氢稀释的硅烷为反应气体,低温条件下成功地制备了系列μc-Si∶H薄膜.对薄膜的厚度测量表明:增大激发频率和反应气压能有效提高沉积速率;随着等离子体功率密度的增大,沉积速率呈现出先增后减的变化.薄膜的Raman光谱、XRD及TEM等测试结果表明:提高衬底温度或减小硅烷浓度,可增大薄膜的结晶度和平均晶粒尺寸;等离子体激发频率的增大只影响薄膜的结晶度,并使结晶度出现极大值;薄膜中存在 (111)、(220)和(311)三个择优结晶取向,且各结晶取向的平均晶粒尺寸不同.

Fabrication of Hydrogenated Microcrystalline Silicon Thin Films at Low Temperature by VHF-PECVD

Using H2-diluted silane,series of μc-Si∶H films are fabricated at low temperature with VHF-PECVD.The thickness measurements reveal that the deposition rates are obviously enhanced with higher plasma excitation frequency or working pressure,but increase firstly and then decrease with the increase of plasma power density.Raman spectra show that the crystallinity and the average grain sizes of the films strongly depend on the temperature of substrate and the concentration of silane.However,the plasma excitation frequency only has effect on the crystallinity,and a maximum occurs during the further increase of plasma excitation frequency.From XRD and TEM experiments,three preferential crystalline orientations (111),(220) and (311) are observed,and the average grain sizes are different for every crystalline orientation.