掺磷氢化纳晶硅薄膜的晶粒尺寸和晶格畸变的研究

Study on the Grain Size and Lattice Strain of Phosphorus-doped Hydrogenated Nanocrystalline Silicon

采用等离子增强化学气相沉积在玻璃衬底上制备了掺磷氢化纳晶硅薄膜,并利用X射线衍射谱(XRD)和拉曼散射谱研究了PH3浓度(GFR=[PH3]/[Si H4])对薄膜平均晶粒尺寸和晶格畸变的影响.结果显示磷弱掺杂有利于晶化,而重掺杂抑制晶化.随着GFR的增大,Si(111)方向上的平均晶粒尺寸呈现出先减小后增大的趋势,而对应的晶格畸变则呈现了相反的变化趋势,小的晶粒尺寸诱导了大的晶格畸变.该结果可归结于与平均晶粒尺寸相关的表面增强效应.在掺磷氢化纳晶硅薄膜的制备过程中,PH起了关键的有效掺杂作用.

Phosphorus-doped hydrogenated nanocrystalline silicon （nc-Si（P） ： H） films are deposi- ted on glass substrates by plasma enhanced chemical vapor deposition with PHa as doping source. Effect of the gas flow ratio of PH3 to Sill4 （GFR= [PH3/[SiH4]） is investigated on the average grain size and lattice strain of nc-Si（P） ： H films by X-ray diffractometry and Raman spectroscopy. The results indicate that light phosphorus doping helps the crystallization while heavy doping restrains the crystallization. The average grain size along Si（111） orientation shows an obvious decrease, and then an increase with GFR increasing, whereas the corresponding lattice strain shows an opposite change. Small grain size induces larger lattice strain, which may be attributed to the grain size-related enhanced surface effect. PH3 plays an effective doping role in the preparation process of nc-Si（P） ： H films.