GaN薄膜的椭偏光谱研究  

Study of the GaN Film by Spectroscopic Ellipsometry

作　　者：余养菁[1] 张斌恩[1] 李孔翌[1] 姜伟[1] 李书平[1] 康俊勇[1] 

机构地区：[1]厦门大学物理系教育部微纳光电子材料与器件工程研究中心福建省半导体材料及应用重点实验室,福建厦门361005

出　　处：《半导体技术》2011年第11期821-825,865,共6页Semiconductor Technology

基　　金：国家自然科学基金重点专项(60827004);国家自然科学基金(60776066);国家863计划项目资助项目(2011AA03A110)

摘　　要：采用椭圆偏振光谱法,在1.50～6.50 eV光谱内,研究了在蓝宝石衬底(0001)面上使用金属有机化学气相沉积(MOCVD)的方法制备的非掺杂纤锌矿结构GaN薄膜的光学性质。建立GaN表面层/外延层/缓冲层/衬底四层物理结构模型。与Cauchy和Sellmeier色散公式比较后选择了Tanguy Extended色散公式来分析GaN薄膜的光学性质。椭圆偏振光谱拟合结果表明,Tanguy Extended色散公式能更准确、方便地描述GaN薄膜在全波段(特别是带隙及带隙之上波段)的色散关系。提供了GaN薄膜在1.50～6.50 eV光谱范围内的寻常光(o光)和非寻常光(e光)折射率和消光系数色散关系,为定量分析GaN薄膜带边附近各向异性的光学性质提供了依据。Optical property of wurtzite GaN film was investigated by spectroscopic ellipsometry （SE） in the spectrum range of 1.50 -6.50 eV. Unintentionally doped wurtzite GaN film was fabricated by metal-organic chemical vapor deposition （MOCVD） on （0001） sapphire. Four-layer physical structure model including surface layer, epilayer, buffer layer and substrate was built by analysis. Compared with common dispersion formulas such as Cauchy and Sellmeier, Tanguy Extended dispersion formulas was used to characterize optical property of wurtzite GaN film. According to the fitting result of SE, Tanguy Extend dispersion formulas can well characterize dispersion relation of refractive and extinction index with full waveband, especially around and above bandgap. The dispersion relation of refractive and extinction index of ordinary （o） and extraordinary （ e ） was offered, which is the base of quantitative analysis of anisotropic optical property of GaN film.

关 键 词：GAN薄膜 椭圆偏振光谱 光学各向异性 色散关系 纤锌矿结构 

分 类 号：TN304.2[电子电信—物理电子学] O433.4[机械工程—光学工程]