HWE生长条件对CdTe/Si薄膜结构特性的影响

研究了热壁外延(HWE)生长条件对Si(100)衬底上沉积外延的多晶CdTe薄膜的晶粒尺寸和取向的影响.用SEM和XRD技术分析了不同外延时间、不同衬底温度及不同源温下外延膜的表面形貌和结构特征.SEM发现随着外延时间的增加或衬底温度的提高,晶粒尺寸明显增大;XRD显示所有的外延薄膜均为面心立方结构,并高度显示优势取向(111),且随着衬底温度或薄膜厚度的增加,(111)峰的衍射强度增加,显示薄膜的择优取向更好.其原因是面心立方结构中,(111)表面具有的表面自由能最低.通过对不同外延时间下薄膜厚度的测试发现,薄膜具有加速生长趋势.衬底温度及源温对外延层厚度均有较大的影响.

Influence of HWE Growth Conditions on the Structural Properties of CdTe/Si Thin Films

The grain size and orientation of polycrystalline CdTe thin films grown under different conditions by HWE on Si(100) substrate were studied.The surface morphologies and structural performance grown under different epitaxial time as well as different source temperatures and different substrate temperatures were evaluated by SEM and XRD,respectively.SEM reveals that the average grain size increases with the increase of the growth time and substrate temperature.All samples show that the main features of the XRD patterns are the same,which has a nice cubic phase preferential(111) orientation,but only the peak intensity increase with the increase of substrate temperature and growth time.It is also reported that the film growth has an acceleration by the analysis of film thickness under different growth time,and the film thickness depends a lot on both the source and substrate temperature.