GaN基外延膜的激光剥离和InGaNLD外延膜的解理

利用波长为248nm的KrF准分子激光器进行了蓝宝石衬底GaN外延层剥离。对极薄的MOCVD生长的单层GaN外延膜(3μm)和InGaNLD外延膜(5μm)实现了大面积剥离。对剥离蓝宝石衬底背面抛光和未抛光外延片的不同特点作了比较,激光剥离所需的能量密度阈值分别约为200mJ/cm2和300mJ/cm2,优化结果表明,能量密度分别在400mJ/cm2和600mJ/cm2可实现稳定的剥离。同时对剥离后的InGaN多量子阱LD结构薄膜进行了解理,SEM观察显示获得的InGaNLD腔面平整光滑。基于这种技术可以获得无蓝宝石衬底的GaN基光电子和电子器件。

Thin film GaN-based membranes by laser lift-off and cleaved InGaN LD facet

Thin gallium nitride films,grown on sapphire substrates by MOCVD,are debonded by laser-induced lift-off. 3μm thick GaN membranes and 5μm thick InGaN MQW LD membranes are successfully separated from the growth substrates using KrF pulsed-excimer laser.Characterization of laser lift-off technology between wafers with sapphire substrates backside polished and wafers with sapphire substrates backside unpolished are compared.The threshold intensities are about 200mJ/cm² and 300mJ/cm² for these two kinds of wafers,and incident pulse intensities of 400mJ/cm² and 600mJ/cm² were required for stable interface splitting respectively. The InGaN MQW LD films are transfired onto a Si or InP support substrate and then cleaved. SEM was employed to analyze the cleaved facet. It can be concluded that the cleaved facet is ideal. GaN-based opto-electronic and electronic devices without sapphire substrate are available with this technology.