溅射AlN技术对GaN基LED性能的影响

Effects of Sputter AlN Technology on GaN-Based LED Performances

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 AlN thin film growth technology by magnetron sputtering on the patterned sapphire substrate（ PSS） was researched,and the GaN-based LED was grown on these AlN thin films by Metal organic chemical vapor deposition（ MOCVD）. Through a series of comparative experiments, the influence of the preparation conditions of AlN thin films on the crystal quality of GaN epitaxial layer was analyzed,and the effects of N2 pretreatment power before sputtering,thermal treatment temperature after sputtering on the performances of the GaN-based LED was studied. The experimental results indicate that the thicker AlN film leads to higher nucleation density in GaN buffer,lower screw threading dislocation（ TD） density and higher edge TD density in GaN epitaxy film. N2 treatment power increases caused the surface lattice damages more seriously,and results in higher screw TD in GaN epitaxy film. The increasing thermal treatment temperature makes rougher the surface and higher nucleus density,which cause lower screw TD density and higher edge TD density in GaN epitaxy film. Then the variations of TD density on GaN epitaxy film aforementioned further effect the optical-electrical characteristics of LED significantly.