摘要:系统研究了HCl的载气、NH,的载气、总N,载气流量以及镓源反应温度和外延生长温度对氢化物气相外延技术在C面蓝宝石上生长的GaN膜晶体质量的影响,并利用高分辨X射线衍射技术,喇曼光谱和光致发光谱对生长的外延膜进行表征。结构表征发现,优化的N,载气流量、镓源反应温度和外延生长温度生长得到的GaN膜具有优良的晶体质量和光电特性。测试结果表明,载气流量的改变影响生长系统中的寄生沉积、GaN膜生长表面过饱和度与Ga和N源气体原子团的气体输运;优化的生长温度可以增强GaN膜的横向外延并促进其二维模式生长,进而有利于生长高质量并具有光滑平面的GaN外延膜。
The effects of N2 carrier gas flow of HC1, NH3 and total N2, the reaction temperature of gallium source and growth temperature on GaN film grown on c-sapphire by hydride vapor phase epitaxy (HVPE) were investigated. The properties of GaN epilayers were characterized by high-resolution X-ray diffraction (HRXRD), Raman spectra and photoluminescence (PL) measurements. The experimental characterizations indicate that the GaN film has good crystal and optoelectronic properties, which has been grown at the optimized N2 carrier gas flow, reaction temperature of gallium source and growth temperature. The measurement results show that the N2 carrier gas flow affects the parasitic reactions, the growth super-saturation of growth front and the transporting of the Ga or N radicals. The optimized growth temperature can enhance the lateral growth and promote the two-dimensional (2D) growth, which benefits the growth of high-quality crystal GaN layer with smooth surface.