HVPE法制备高质量GaN单晶研究

发布时间：2018-02-28 12:34

本文关键词： 氢化物气相外延 GaN单晶自支撑激光剥离　出处：《天津大学》2015年硕士论文　论文类型：学位论文

【摘要】：氮化镓(GaN)是第三代宽禁带半导体材料研究中的热点。在光学性质方面,氮化镓材料为直接带隙,禁带宽度为3.4eV,其合金带隙覆盖了从红色到紫色的光谱范围,尤其适合在紫外、蓝光器件方面的应用;在物理化学性质方面,GaN具有化学稳定性好、不易被腐蚀,熔化温度高、热传导性能优良、抗辐射等优点;在电学性质方面,GaN具有很高的击穿电压和电子迁移率,且介电常数低,决定了氮化镓器件将具有很高的性能。这些优点使氮化镓在光电子、微电子器件领域具有重要的应用潜力。本文首先对GaN材料的发展、常用衬底、主要表征手段进行了综述介绍,进而对在蓝宝石衬底上氢化物气相外延(HVPE)法生长GaN进行了工艺研究,研究内容包括高质量厚层GaN单晶生长工艺研究、降低生长GaN单晶层弯曲度研究以及衬底分离技术研究。主要研究成果如下:(1)通过选用不同掩膜图形开展试验研究,确定了条形掩膜图形更利于初期掩膜长合,可有效抑制位错延伸,对降低位错密度效果明显。(2)通过V/III比例、生长温度、生长压力、载气等生长工艺参数的调节,分析各参数对晶体质量、晶片弯曲的影响,最终生长出厚度大于60μm、表面光滑无坑,位错密度在106cm-2以下,表面粗糙度Ra(2μmx2μm)在0.1nm以下的厚层GaN基片。(3)生长出厚度大于300μm超厚层GaN基片,采用激光剥离技术进行衬底去除,通过试验结果验证,详细介绍了影响激光分离的因素,最终获得完整2英寸自支撑GaN单晶衬底材料。(4)采用插入层技术,结合边缘保护技术实现超厚层GaN基片自剥离,获得厚度大于450μm,直径45mm的自支撑GaN单晶衬底材料。
[Abstract]:Gallium nitride (gan) is a hot spot in the research of the third generation wide band gap semiconductor materials. In terms of optical properties, gallium nitride material has a direct band gap and a band gap of 3.4 EV. The alloy band gap covers the spectrum range from red to purple, and is especially suitable for UV. In physical and chemical properties, gan has the advantages of good chemical stability, low corrosion resistance, high melting temperature, excellent thermal conductivity and radiation resistance. In terms of electrical properties, gan has high breakdown voltage, electron mobility and low dielectric constant, which determines the high performance of gallium nitride devices. These advantages make gallium nitride in photoelectron. Microelectronic devices have important application potential. Firstly, the development of GaN materials, common substrates and main characterization methods are reviewed. Furthermore, the growth process of GaN on sapphire substrate by hydride vapor phase epitaxy (Hve) method was studied. The research contents include the growth process of GaN single crystal with high quality and thick layer. The main research results are as follows: (1) by selecting different mask patterns to carry out experimental research, it is determined that the strip mask pattern is more favorable to the initial mask length and combination. It can effectively restrain dislocation extension, and has obvious effect on reducing dislocation density. (2) by adjusting the growth process parameters such as V / III ratio, growth temperature, growth pressure, carrier gas and so on, the effects of these parameters on crystal quality and wafer bending are analyzed. Finally, the thick GaN substrate with thickness more than 60 渭 m, smooth surface without pits, dislocation density below 106 cm-2 and surface roughness Ra(2 渭 mx2 渭 m) was grown. The GaN substrate with thickness more than 300 渭 m was grown. The substrate was removed by laser stripping technique. The experimental results show that the factors affecting laser separation are introduced in detail. Finally, the complete 2 inch self-supporting GaN substrate material. The insertion layer technique and edge protection technology are used to realize the self-stripping of the super-thick GaN substrate. Self-supporting GaN substrates with thickness of more than 450 渭 m and diameter of 45 mm were obtained.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.05

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