MOCVD生长的InN薄膜中In分凝现象  

Study on In Segregation in InN Films Grown by Metal-organic Chemical Vapor Deposition

作　　者：徐峰[1] 陈敦军[1] 张荣[1] 谢自力[1] 刘斌[1] 刘启佳[1] 江若涟[1] 郑有阧[1] 

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

出　　处：《发光学报》2008年第5期851-855,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金(60476030;60421003;60676057);"973"专项基金(2006CB604905;2006CB604907);新世纪优秀人才计划(NCET-05-0445);江苏省自然科学基金(BK2006126)资助项目

摘　　要：利用金属有机物化学气相淀积(MOCVD)方法不同生长条件下在c面蓝宝石衬底上制备了InN薄膜,通过不同的物理表征手段研究了InN薄膜的物理性质,结果表明:合适的生长温度可以抑制InN薄膜表面分凝现象。研究认为较低的生长温度使作为N源的NH3分解率较低,In—N的成键可能性小,导致In在表面聚集出现分凝;而较高生长温度时,InN薄膜中In—N键能较小,易发生断裂,反应活性较强的N和H原子逸离薄膜表面,In滞留在薄膜表面也导致In分凝现象的出现。相对于表面分凝的样品,未出现表面分凝的样品的薄膜晶体质量和表面形貌也得到了提高。同时,通过Raman散射谱研究了晶格振动E2声子模的应力效应。InN materials have been attracting a lot of attention for its prominent application in electronic and optical devices, compared with GaN and AlN, InN has smaller effective mass and higher electron drift velocity. However, the growth difficulties due to low growth temperature and lack of lattice-matched substrate restricted the evolution of InN-based devices, more and more efforts are made in efficiently deposit InN films with better quality. InN films were synthesized on the （0001） sapphire substrates at different growth temperatures by metal organic chemical vapor deposition （MOCVD）, the growth source materials are trimethylindium （TMI）, trimethylgallium（TMG） and ammonia（ NH3 ）. The physical properties of the films were characterized by a series of measurements. We fully studied the characteristic of InN films by various methods, such as X-ray diffraction （XRD）, atomic force microscope （AFM）, X-ray photoelectron spectroscopy （XPS） and Raman measurements. It＇s well known that the growth temperature is one of the most important parameters in InN films, so in our study, we focus our attention mainly on the effect of growth of temperature. It was found that 600 ℃ is a suitable growth temperature for InN films, the suitable temperature can inhibit the surface segregation phenomenon of In on the surface of InN films. But at a lower or higher temperature it will lead to a surface segregation of In on the InN films. The crystalline quality and morphology of the surface for the sample without surface segregation have been improved compared with the samples with surface segregation. In addition, it was also found that the residual strain in InN films increased with increasing growth temperature by Raman analysis, the E2 （high） model frequency shift toward high frequency with increasing growth temperature, and this shift is due to the presence of residual thermal strain in the InN film. When the growth temperature is lower, the residual thermal strain came into being due to the diffe

关 键 词：In分凝 X射线衍射 原子力显微镜 X射线光电子谱 RAMAN散射 

分 类 号：O472.1[理学—半导体物理]