非故意掺杂GaN薄膜方块电阻与载气中N_2比例关系研究  

Dependence of GaN film sheet resistance on the N_2 carrier gas percentage

作　　者：席光义[1] 郝智彪[1] 汪莱[1] 李洪涛[1] 江洋[1] 赵维[1] 任凡[1] 韩彦军[1] 孙长征[1] 罗毅[1] 

机构地区：[1]清华大学电子工程系清华大学信息科学与技术国家实验室/集成光电子学国家重点实验室,北京100084

出　　处：《物理学报》2008年第11期7233-7237,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60536020;60723002);国家重点基础研究发展计划(973)项目(批准号:2006CB302801;2006CB302804;2006CB302806;2006CB921106);国家高技术研究发展计划(863)(批准号:2006AA03A105);北京市科委重大计划(批准号:D0404003040321)资助的课题~~

摘　　要：利用金属有机气相外延方法研究了非故意掺杂GaN薄膜的方块电阻与高温GaN体材料生长时载气中N2比例的关系.研究发现,随着载气中N2比例的增加,GaN薄膜方块电阻急剧增加.当载气中N2比例为50%时,GaN薄膜方块电阻达1.1×108Ω/□,且GaN表面平整,均方根粗糙度为0.233 nm.二次离子质谱分析发现,载气中N2比例不同的样品中碳、氧杂质含量无明显差别.随着载气中N2比例的增加,GaN材料中螺型位错相关缺陷密度无明显变化,而刃型位错相关缺陷密度明显增加.结果表明,刃型位错的受主补偿作用是导致GaN薄膜方块电阻变化的主要原因.In this paper, GaN films are grown by metal organic vapor phase epitaxy. Different N2 carrier gas percentages were used in the high-temperature growth process of the bulk GaN, and the dependence of sheet resistance on N2 carrier gas percentage is studied. It is found that the sheet resistance of the GaN film increases dramatically with N2 carrier gas percentage. When N2 carrier gas percentage is 50%, the sheet resistance of the GaN film is 1.1 × 10^8Ω/sq, and the surface root-mean-square roughness is as small as 0. 233 nm. Secondary ion mass spectroscopy measurements reveal that the concentration of carbon and oxygen impurities is almost the same in the samples with different N2 carrier gas percentage. The density of edge-dislocation-related defects increases with N2 cartier gas percentage, while the density of screw-dislocation-related defects shows no obvious difference for all the samples. Our results indicate that the increase of the sheet resistance of GaN film is mainly due to the increase of edge threading dislocations, which act as acceptor centers in the GaN material.

关 键 词：半绝缘GaN薄膜 载气 金属有机气相外延 位错 

分 类 号：O484[理学—固体物理]