PVT法生长ZnTe晶体的技术

Technology of ZnTe Crystal Growth by PVT

采用无籽晶物理气相传输(PVT)方法生长出ZnTe晶体。实验开始,温差较大,压强相对较低,造成晶体生长速率过快,从而以各成核点为中心进行岛状生长,形成了结构密集的ZnTe多晶结构。实验过程中,通过调整原料区与生长区温差和压强等工艺条件进行一系列籽晶扩大实验。发现适当缩小温差、增加生长压强有益于籽晶横向扩展。当温差缩小到35℃,压强增加到230 mbar(1 mbar=102 Pa),生长出了直径45 mm、厚度8 mm的ZnTe单晶。观察发现,晶体表面存在明显的孪晶线,孪晶线产生原因为生长前籽晶边缘有破损,导致生长过程突变。取其较大的单晶进行XRD测试,结果显示该ZnTe单晶具有良好的〈111〉晶向和结晶质量。

The ZnTe crystal was grown with the physical vapor transport （PVT） method of seedless crystal. In the beginning of the experiment, the temperature difference was bigger and the pressure was relatively low, resulting in the growth rate of crystal too fast, then the crystal grew around the nucleation point in the volmer-weber mode and the dense ZnTe polycrystalline structure was formed. During the experiment, by adjusting the pressure and the temperature difference between the raw material area and growing region, a series of seed crystal expanding experiments were carried out. It is found that in a certain extent, the less temperature difference and higher pressure are beneficial to the seed crystal lateral extension. When the temperature difference is 35℃ and the pressure is 230 mbar （1 mbar = 102 Pa）, the ZnTe single crystal is formed with the diameter of 45 mm and the thickness of 8 mm. It can be observed that there is clear twin lines on the surface of the ZnTe single crystal, the reason is the growth process mutation caused by the damage on the edge of the seed crystal before growth. The XRD test result of the large single crystal shows that the ZnTe single crystal has good （111） crystal orientation and crystallization quality.