氢化物气相外延生长的GaN厚膜中位错密度计算  

Determination of Dislocation Density in HVPE-GaN Layer

作　　者：刘战辉[1,2] 修向前[1] 张荣[1] 谢自力[1] 颜怀跃[1] 施毅[1] 顾书林[1] 韩平[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 [2]南京信息工程大学数理学院,南京210044

出　　处：《半导体技术》2008年第S1期190-192,201,共4页Semiconductor Technology

基　　金：国家"973"重点基础研究项目(2006CB6049);国家"863"高技术研究发展计划(2006AA03A103;2006AA03A118;2006AA03Z411);国家自然科学基金(60721063;60676057;60731160628;60710085;60776001;60820106003);江苏省创新学者攀登项目(BK2008019);南京大学研究生科研创新基金资助

摘　　要：采用两种不同的方法分别确定了在c面蓝宝石上用氢化物气相外延(HVPE)法生长的六方相的GaN厚膜中的位错密度。首先,利用选择性化学腐蚀方法研究了GaN膜中的晶体缺陷,研究区分了位错的不同类型,发现在HVPEGaN贯通位错占主导地位。由腐蚀后形成的腐蚀坑数量可以直接来确定膜中的位错密度。此外,研究了用特定的X射线衍射峰半峰宽数据计算得到位错密度的方法。结果表明,HVPE生长的六方相的GaN厚膜中的位错密度为109～1010cm-2,而且两种方法所得到的结果相符合。The dislocation density in hexagonal GaN epitaxial layers grown on c-plane sapphire substrates by hydride vapor phase epitaxy(HVPE)was measured by two different methods.By means of defect-selective etching(orthodox etching in molten KOH),the dislocation defects in GaN epitaxial films were studied.From surface morphology pictures and cross-sectional images,these defects could be divided into various types.Among all the defects,threading dislocations(TDs)dominated in the GaN epilayers.The density of TDs could be directly determined by accounting the different etching pits after the specimen etched.On the other hand,the dislocation density was also derived from the full-width half-maximum(FWHM)of certain X-ray diffraction(XRD)peaks.The results show that the two individual methods are in good agreement with each other and the density of wurtizite GaN epitaxial layers grown by HVPE is in the order from 109 cm-2 to 1010 cm-2.

关 键 词：位错 氮化镓 氢化物气相外延 X射线衍射 

分 类 号：O474[理学—半导体物理]