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根据物理气相传输法(PVT)AlN晶体生长特点及工艺要求,自主设计了AlN晶体生长炉及其配套热场。FEMAG软件热场模拟结果表明,自主设计的晶体生长炉及其配套热场可以达到AlN晶体生长所需坩埚内部温度梯度要求。基于设计的PVT生长炉,开展了在2 250℃生长温度、40h长晶时间条件下的自发形核生长实验。实验研究结果表明,在该工艺条件下,通过自发形核可生长得到典型长度为3~5mm、直径为2mm的高质量AlN单晶;AlN晶体的c-plane(0001)生长速率最快,易形成尖锥形晶体结构,不利于晶体的扩径;Raman表征图谱中AlN晶体的E2(high)半峰宽仅为5.65cm-1,表明AlN晶体质量非常高;SEM、EDS分析得出晶体内部质量较为均匀,c-plane和m-plane腐蚀形貌特征明显。
According to the growth characteristics and technological requirements of AlN crystal in physical vapor transport (PVT), the AlN crystal growth furnace and its matching thermal field were independently designed. FEMAG software simulation results show that the independently designed crystal growth furnace and its accompanying thermal field can meet the crucible internal temperature gradient requirement for AlN crystal growth. Based on the designed PVT growth furnace, spontaneous nucleation experiments at growth temperature of 2 250 ℃ and growth time of 40h were carried out. Experimental results show that under the conditions of this process, high quality AlN single crystals with typical length of 3 ~ 5mm and diameter of 2mm can be obtained by spontaneous nucleation. The c-plane (0001) growth rate of AlN crystal is the fastest, The sharp peak of E2 (high) of AlN crystal in Raman characterization spectrum is only 5.65cm-1, indicating that AlN crystal has a very high quality. The SEM and EDS analysis show that the crystal inside The quality is more uniform, c-plane and m-plane corrosion morphology is obvious.