【摘要】 采用低压化学气相沉积法(LPCVD),分别在n-Si和SiO2衬底上制备Si1-xGex薄膜。Ge的组分比由俄歇电子谱(AES)测定。对n-Si和SiO2衬底上的Si1-xGex分别进行热扩散和热退火处理,以考察热扩散和退火条件对薄膜物理及电学特性的影响。薄膜的物相由X射线衍射(XRD)确定。其薄层电阻、载流子迁移率及浓度分别由四探针法和霍尔效应法测定。基于XRD图谱,根据Scherer公式,估算出平均晶粒大小。数值拟合得到霍尔迁移率与平均晶粒尺寸为近似的线性关系,从而得出LPCVD-Si1-xGex薄膜的电输运特性基本符合Seto模型的结论。更多还原

【Abstract】 Si1-xGex thin films were fabricated on n-Si and SiO2 substrates,respectively,by low pressure chemical vapor deposition(LPCVD).The Ge fraction in the Si1-xGex layer was determined by Auger electron spectroscopy(AES).The samples were thermally diffused and annealed to investigate diffusion and annealing conditions on the physical and electrical properties of the films.Phase identification was performed by X-ray diffractometry(XRD).The sheet resistance and Hall mobility,as well as concentration of carriers,were measured by four-probe technique and Hall effect measurement.Based on the XRD spectra and Scherer’s formula,the average grain size of the annealed Si1-xGex thin films was calculated.It can be obtained by fitting that the Hall mobility has a nearly linear dependence on the average grain size.So,the electrical transport characteristics of the LPCVD Si1-xGex fundamentally conforms with Seto’s model.更多还原