AlN/Si(111)衬底上4H-SiC的CVD外延生长研究  

Study of Heteroepitaxial 4H-SiC Films Growth on AlN/Si(111) Substrates by CVD

作　　者：吴军[1] 王荣华[1] 韩平[1] 梅琴[1] 刘斌[1] 谢自力[1] 修向前[1] 张荣[1] 郑有炓[1] 

机构地区：[1]南京大学物理系江苏省光电信息功能材料重点实验室,南京210093

出　　处：《半导体技术》2008年第S1期262-265,共4页Semiconductor Technology

基　　金：国家自然科学基金(60721063);高等学校博士学科点专项基金(20050284004)

摘　　要：利用CVD的方法在Al N/Si(111)衬底上成功实现了4H-SiC薄膜的异质外延生长,用高分辨X射线衍射仪(HRXRD)、扫描电子显微镜(SEM)、喇曼散射(Raman scattering)对所得样品的结构特征、表面形貌等进行了表征测量。XRD测量结果显示得到的SiC薄膜具有单一的晶体取向;Raman散射谱线初步表明得到的SiC薄膜为4H型态。衬底温度过低,不利于Si、C原子选择合适的格点位置成键,外延薄膜晶体质量不高;衬底温度过高,H2的刻蚀作用和表面原子的解吸附作用增强,不利于SiC的成核生长。C/Si比过小,薄膜表面会形成Si的小液滴;C/Si比过大,薄膜中会产生Si空位形式的微缺陷。因此,研究表明在Al N/Si(111)衬底上外延4H-SiC的最佳衬底温度为1230~1270℃,较为理想的C/Si比值为1.3。The 4H-SiC films heteroepitaxially deposited on AlN/Si(111)substrates by chemical vapor deposition(CVD)were investigated.High-resolution X-ray diffraction(HRXRD),scanning electron microscope(SEM)and Raman scattering were used to analyze the crystallographic properties and surface morphology of these SiC films.The XRD spectrum shows that the SiC films have single(0006)orientation.The spectrum of Raman scattering indicates that the type of the prepared SiC films is 4H.It is found that lower substrate temperature is not beneficial for Si and C atoms to select the proper sites,leading to poor crystalline quality.While higher substrate temperature enhances the etching effect of H2 and desorption of absorbed atoms,which goes against the film growth.In addition,the ratio of C/Si influences on the growth of SiC as well.Excess Si results droplets on the surface,while excess C causes Si vacancies in the material.These experiments show that the preferred substrate temperature for 4H-SiC heteroepitaxy is at 1 230-1 270 ℃,the proper ratio of C/Si equals to 1.3.

关 键 词：AlN/Si(111)衬底 4H-SiC薄膜 异质外延 碳硅比 

分 类 号：TN304.055[电子电信—物理电子学]