KOH热湿腐蚀法准确估算GaN的位错密度.PDF

第 14卷第 4 期 功能材料与器件学报 Vo l14 ,No4 2008年 8月 JOURNAL OF FUNCTIONAL MA TER IAL S AND D EV ICES A ug. , 2008 文章编号 : 1007 - 4252 (2008) 04 - 0742 - 09 Reliab le eva lua tion of d isloca tion den sities in GaN ep ilayer s by m olten KO H etch ing GAO Zh i - Yuan , HAO Yue, ZHAN G J in - Cheng, ZHAN G J in - Feng, N I J in - Yu ( Key L aboratory of M in istry of Education for W ide B and - Gap Sem iconductor M aterials and D evice s, Schoo l of M icroelectron ic s, X idian U n iversity, X i’an 7 1007 1, Ch ina) A b stract: The pu rpo se of th is p ap er is to deal w ith the con troversy in the literatu re abou t the origin s of the hexagonal - shap ed etch p its in GaN ep ilayers form ed by wet - chem ical etch ing, and get a better e stim a tion of dislocation den sitie s. In ten sive ob servation s of GaN etch ing by mo lten KOH are focu sed on the morp ho logy evo lu tion du ring etch ing and the dep endence of etch ing on tim e and temp eratu re. It is the three - dim en sional shap e of etch p its that cou ld be correlated w ith the dislocation typ e, in stead of the size a s m any literatu re s p re sen ted, and po larity is found to be re spon sib le for the form ation of the se differ en t etch p it shap e s. In add ition , the needed etch ing tim e to reveal all the dislocation s decrea se s w ith in crea sing needed temp eratu re. A com b ination of the op tim um etch ing condition and the p rop er m icro scop y m ea su rem en t lead s to a reliab le evaluation of dislocation den sitie s in GaN. Key words: d islocation den sity; GaN ; EPD ; etch ing m echan ism CL C : 6 170J , 7280E　　D ocum en