• •

高温退火对PVT法生长的AlN晶体质量的影响

1. 山东大学 新一代半导体材料研究院,晶体材料国家重点实验室,济南 250100
• 收稿日期:2022-08-13 修回日期:2022-10-09
• 作者简介:俞瑞仙(1987-), 男, 博士研究生. E-mail: yuruixian0001@126.com

Effect of High-temperature Annealing on AlN Crystal Grown by PVT Method

YU Ruixian, WANG Guodong, WANG Shouzhi, HU Xiaobo, XU Xiangang, ZHANG Lei

1. Institute of Novel Semiconductors, State Key laboratory of Crystal Material, Shandong University, Jinan 250100, China
• Received:2022-08-13 Revised:2022-10-09
• About author:YU Ruixian (1987-), male, PhD candidate. E-mail: yuruixian0001@126.com
• Supported by:
National Natural Science Foundation of China (51872164, 52202265); Shenzhen Science and Technology Program (JCYJ20210324141607019)

Abstract: In the process of PVT growth of AlN crystals, it is difficult to maintain ideal thermodynamic equilibrium conditions, thus crystal defects are inevitably generated. High temperature annealing technology has received much attention due to their effectiveness in improving crystal integrity. However, there are few reports on the high temperature annealing of AlN crystals grown by PVT method. In this paper, AlN samples grown by PVT method were annealed at high temperature in N2 atmosphere. In order to evaluate the crystalline quality and structural perfection of AlN before and after thermal annealing, high-resolution X-ray diffraction (HRXRD) and Raman spectrum were carried out. In addition, the impurity related band gap changes in the optical properties of AlN crystals were characterized by room temperature photoluminescence (PL) and absorption spectra. The crystal quality of these AlN crystals was significantly improved after annealing at 1400-1800 ℃. The full width at half maximum (FWHM) of the (10-12) plane X-ray rocking curve decreased from 104.04 to 79.92 arcsec after annealing at 1400 ℃. As the annealing temperature increases, the absorption was significantly enhanced and the band gap become larger, indicating that the annealing process is beneficial to improve the quality of AlN crystals. The results of secondary ion mass spectrometry (SIMS) show that the annealing process reduces the C impurity, resulting in an increase in the band gap of AlN crystal, which is consistent with the results of optical absorption.