基于PVT法自发形核生长AlN晶体的研究

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、40 h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～Smm、直径为2 mm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5.65 cm-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.

Study on Spontaneous Nucleation of AlN Single Crystal by PVT Method

The aluminum nitride (AlN) crystal growth furnace and its supporting thermal field were designed according to the growth characteristics and process requirements of PVT method.The simulation results of FEMAG software showed that the growth furnace could meet the requirements of the internal temperature gradient of the crucible.The growth habit and quality of AlN crystals with length of 3～5 mm and diameter of 2 mm were obtained at 2 250 C and 40 h.The AlN crystal growth exhibited the fastest growth rate of c-plane (0001),which was easy to form a cone-shaped crystal structure,thus not conducive to the expansion of the crystal.The E2 (high) half-peak width of the AlN crystal in the Raman spectrum was 5.65 cm-1,indicating that the AlN crystal quality was very high.The SEM and EDS analysis showed that the internal mass of the crystal was uniform and the c-plane and m-plane corrosion morphology was obvious.