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研究了在图形蓝宝石衬底(PSS)上利用磁控溅射制备AlN薄膜的相关技术,随后通过采用金属有机化学气相沉积(MOCVD)在相关AlN薄膜上生了长GaN基LED。通过一系列对比实验,分析了AlN薄膜的制备条件对GaN外延层晶体质量的影响,研究了AlN薄膜溅射前N2预处理功率和溅射后热处理温度对GaN基LED性能的作用机制。实验结果表明:AlN薄膜厚度的增加,导致GaN缓冲层成核密度逐渐升高和GaN外延膜螺位错密度降低刃位错密度升高;N2处理功率的提升会加剧衬底表面晶格损伤,在GaN外延膜引入更多的螺位错;AlN热处理温度的升高粗化了表面并提高了GaN成核密度,使得GaN外延膜螺位错密度降低刃位错密度升高;而这些GaN外延膜位错密度的变化又进一步影响到LED的光电特性。
The related art of preparing AlN films by magnetron sputtering on a patterned sapphire substrate (PSS) was studied, followed by the growth of GaN-based LEDs on the relevant AlN films by using metal organic chemical vapor deposition (MOCVD). Through a series of comparative experiments, the influence of the preparation conditions of AlN thin films on the quality of GaN epitaxial layers was analyzed. The mechanism of N2 pretreatment power and the post-sputtering heat treatment temperature on the properties of GaN-based LEDs was investigated. The experimental results show that the increase of AlN film thickness leads to the increase of nucleation density of GaN buffer layer and the decrease of dislocation density of GaN epitaxial film. The increase of N2 treatment power will aggravate the lattice damage of substrate surface, The introduction of more screw dislocation in the GaN epitaxial film; AlN heat treatment temperature roughening of the surface and increase the GaN nucleation density, making GaN epitaxial film screw dislocation density to reduce edge dislocation density increased; and these GaN epitaxial The change of the dislocation density further affects the photoelectric properties of the LED.