高均匀性6英寸GaN厚膜的高速率HVPE生长研究

doi:10.16553/j.cnki.issn1000-985x.2024.0227

摘要/Abstract

摘要： 氢化物气相外延(HVPE)是制备GaN单晶衬底的关键技术,由于生长速率较高,如何控制大尺寸GaN高速率高均匀性生长对于获得高质量GaN衬底具有重要意义。本文针对自主设计研制的6英寸(1英寸=2.54 cm)GaN衬底用HVPE设备,通过数值模拟和实际生长实验,研究了工艺参数如源气体与衬底距离D、分隔气体、HCl流量、NH₃载气流量等对高速率生长GaN膜厚度均匀性的影响。数值模拟与生长实验结果发现,采用自研HVPE设备生长GaN厚膜具有高生长速率和高厚度均匀性等特点。研究表明,引入分隔气体及适当增大D值可以有效促进GaCl气体向样品边缘扩散,从而显著提升大尺寸外延厚膜的均匀性。采用最终优化工艺条件获得了厚度约11 μm 的6英寸GaN厚膜,其厚度不均匀性约±1.5%,生长速率大于60 μm/h;随着生长时间的增加,生长速率增大,在生长时间为3 h时,6英寸GaN厚膜厚度达到约700 μm,生长速率增大至200 μm/h以上,且厚度不均匀性仍在±5%以内。

关键词: 氮化镓, 氢化物气相外延, 晶体生长, 数值模拟, 厚度不均匀性

Abstract: Gallium nitride (GaN) is an ideal semiconductor material for the development of microelectronic and optoelectronic devices. Homo-epitaxial growth on high-quality GaN single crystal substrates is the fundamental way to achieve high performance of GaN-based devices. Hydride vapor phase epitaxy (HVPE) is currently a most common approach for manufacturing the vast majority of commercially available GaN substrates. Owing to its high growth-rate, how to control the growth of HVPE-GaN with high growth-rate and high uniformity is of great significance for obtaining large-size high quality GaN substrates. Here, HVPE equipment for 6-inch GaN substrate is designed and developed independently. The effect of growth conditions such as the distance between source gas and substrate (D), separator gas, HCl and NH₃ carrier gas flow-rates on the thickness-uniformity of as-grown GaN films have been studied with the help of numerical simulation and epitaxy experiments. Simulation and experimental results indicate that the self-developed HVPE system has the characteristics of high growth-rate and high thickness-uniformity. The introduction of separator gas and increasing D can effectively promote the diffusion of GaCl gas to the edge of substrates, so as to significantly improve the thickness-uniformity of the large size epitaxial thick films. By further optimizing the growth conditions, 6-inch GaN film with a thickness of ~11 μm achieved thickness-nonuniformity about ±1.5% and growth-rate more than 60 μm/h. The growth-rate increases as the growth time increases. When the growth time is 3 h, the thickness of 6-inch GaN thick film is ~700 μm, the growth rate increases to >200 μm/h and the thickness-nonuniformity is still in the range of ±5%. The corrosion effect of non-reactive HCl on the deposited GaN on the quartz tube wall may lead to the increase of GaCl concentration and thus increase the growth rate. The results will help us to design the large-size HVPE growth system and prepare large-area and high quality GaN substrates.

Key words: gallium nitride, hydride vapor phase epitaxy, crystal growth, numerical simulation, thickness nonuniformity

中图分类号:

O484
O78

许万里, 甘云海, 李悦文, 李彬, 郑有炓, 张荣, 修向前. 高均匀性6英寸GaN厚膜的高速率HVPE生长研究[J]. 人工晶体学报, 2025, 54(1): 11-16.

XU Wanli, GAN Yunhai, LI Yuewen, LI Bin, ZHENG Youdou, ZHANG Rong, XIU Xiangqian. High Rate HVPE Growth of High Uniformity 6-Inch GaN Thick Film[J]. Journal of Synthetic Crystals, 2025, 54(1): 11-16.

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