【摘要】 采用反应蒸发法在提高了缓冲层的生长温度 ,通过对Si基上GaN样品缓冲层区域的高分辨透射电镜像 (HRTEM)和界面区域的选区电子衍射 (SAED)分析的基础上 ,提出了本系统GaN外延的晶体学位相关系和生长机理。GaN与Si衬底之间存在着下列的晶体学位相关系 :GaN <0 0 0 1 >∥Si<1 1 1 >,GaN <1 1 2 - 0 >∥Si<1 1 0 >。GaN外延生长首先在硅衬底上形成GaN晶核 ,生长出GaN多晶缓冲层 ,GaN多晶层在随后的高温保温过程中重新结晶为择优取向的GaN微单晶层 ,最后以这种微单晶层为模板进行晶体大面积的二维生长。同时还发现较高的缓冲层温度也明显提高了GaN外延层的结晶质量。更多还原

【Abstract】 Based on the analysis of the cross sectional HRTEM image of the GaN/Si interface and the SAED images in the interfacial area with a higher buffer growth temperature, the orientation relationship and growth mechanism of GaN epitaxy on silicon substrates by reactive evaporation method were presented. GaN epitaxy started with nucleus formed on the silicon substrate, then followed by a GaN buffer layer growth at low temperature. This polycrystalline buffer layer recrystallized to highly oriented GaN in a micro single crystal form in subsequent high temperature annealing, with the orientation relationships GaN<0001>∥Si<111> and GaN<112-0>∥Si<110>. Finally a two-dimension growth in large area followed using the micro single crystals as a template. It was also found that the GaN quality was remarkably improved with a higher buffer growth temperature.更多还原