预沉积Ge对Si(111)衬底上SSMBE外延生长SiC薄膜的影响  

Effect of Predeposited Ge on the Growth of SiC Films on Si(111) by SSMBE

作　　者：刘忠良[1] 任鹏[1] 刘金锋[1] 唐军[1] 徐彭寿[1] 

机构地区：[1]中国科学技术大学国家同步辐射实验室,合肥230029

出　　处：《物理化学学报》2008年第7期1160-1164,共5页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(50572100)资助项目

摘　　要：利用固源分子束外延(SSMBE)生长技术,在Si(111)衬底上预沉积不同厚度(0、0.2、1nm)Ge,在衬底温度900℃,生长SiC单晶薄膜.利用反射式高能电子衍射仪(RHEED)、原子力显微镜(AFM)和傅立叶变换红外光谱(FTIR)等实验技术,对生长的样品进行了研究.结果表明,预沉积少量Ge(0.2nm)的样品,SiC薄膜表面没有孔洞存在,AFM显示表面比较平整,粗糙度比较小,FTIR结果表明薄膜内应力比较小.这说明少量Ge的预沉积抑制了孔洞的形成,避免衬底Si扩散,因而SiC薄膜的质量比较好.没有预沉积Ge的薄膜,结晶质量比较差,SiC薄膜表面有孔洞且有Si存在.然而预沉积过量Ge(1nm)的样品,由于Ge的岛状生长,导致生长的SiC表面粗糙度变大,结晶质量变差,甚至导致多晶产生.SiC films were grown at substrate temperature of 900 ℃ by solid source molecular beam epitaxy （SSMBE） on Si（111） with different thicknesses （0, 0.2, 1 nm ） of Ge predeposited on Si prior to the epitaxy of SiC. The films were investigated with reflection high energy electron diffraction （RHEED）, atomic force microscopy （AFM）, Fourier transform infrared spectroscopy （FTIR）. The results indicated that the quality of the film with Ge predeposition of 0.2 nm was the best. The surface of the sample was even and there were no voids observed. The Ge prdeposition of 0.2 nm suppressed the Si diffusion and decreased the void formation. For the sample without Ge predeposition, the roughness of the surface was larger and there were some voids and Si grains on the surface. For the sample with the Ge prdeposition of 1 nm, island growth mode of Ge caused the surface of SiC films rougher and the crystalline quality of SiC film worse and even induced the formation of the polycrystalline SiC film.

关 键 词：锗 预沉积 碳化硅 硅衬底 固源分子束外延 

分 类 号：O613.7[理学—无机化学]