Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Molecules. 2019 Apr 19;24(8):1562. doi: 10.3390/molecules24081562.
In this report, the development of physical vapor transport (PVT) methods for bulk aluminum nitride (AlN) crystal growth is reviewed. Three modified PVT methods with different features including selected growth at a conical zone, freestanding growth on a perforated sheet, and nucleation control with an inverse temperature gradient are discussed and compared in terms of the size and quality of the bulk AlN crystals they can produce as well as the process complexity. The PVT method with an inverse temperature gradient is able to significantly reduce the nucleation rate and realize the dominant growth of only one bulk AlN single crystal, and thus grow centimeter-sized bulk AlN single crystals. X-ray rocking curve (XRC) and Raman spectroscopy measurements showed a high crystalline quality of the prepared AlN crystals. The inverse temperature gradient provides an efficient and relatively low-cost method for the preparation of large-sized and high-quality AlN seed crystals used for seeded growth, devoted to the diameter enlargement and quality improvement of bulk AlN single crystals.
本报告回顾了用于块状氮化铝（AlN）晶体生长的物理气相传输（PVT）方法的发展。讨论并比较了三种具有不同特点的改进 PVT 方法，包括在锥形区选择生长、在穿孔片上自由生长以及利用逆温度梯度控制成核，从它们能够生产的块状 AlN 晶体的尺寸和质量以及工艺复杂性方面进行了比较。具有逆温度梯度的 PVT 方法能够显著降低成核速率，并实现仅生长一个块状 AlN 单晶体的优势，从而生长出厘米级尺寸的块状 AlN 单晶体。X 射线摇摆曲线（XRC）和拉曼光谱测量表明，所制备的 AlN 晶体具有高晶体质量。逆温度梯度为使用籽晶生长法制备大尺寸、高质量的 AlN 籽晶提供了一种高效且相对低成本的方法，有助于块状 AlN 单晶体的直径增大和质量提高。
