Publications Details

Brittle-Ductile Relaxation Kinetics of Strained AlGaN/GaN

Hearne, Sean J.; Han, J.; Lee, Stephen R.; Floro, Jerrold A.; Follstaedt, D.M.

The authors have directly measured the stress evolution during metal organic chemical vapor deposition of AlGaN/GaN heterostructures on sapphire. In situ stress measurements were correlated with ex situ microstructural analysis to directly determine a critical thickness for cracking and the subsequent relaxation kinetics of tensile-strained Al{sub x}Ga{sub 1{minus}x}N on GaN. Cracks appear to initiate the formation of misfit dislocations at the AlGaN/GaN interface, which account for the majority of the strain relaxation.