High Rate HVPE Growth of High Uniformity 6-Inch GaN Thick Film

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

Abstract

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

CLC Number:

O484
O78

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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