Crystallographic Tilt in Aluminum Gallium Nitride Epilayers Grown on Miscut Aluminum Nitride Substrates

Heteroepitaxial crystallographic tilt has been investigated as a possible strain-relief mechanism in Al-rich (Al>50%) AlGaN heteroepitaxial layers grown on single-crystal (0001) AlN substrates with varying miscuts from 0.05° to 4.30°. The magnitude of the elastic lattice deformation-induced increases monotonically miscut angle, tightly following Nagai model. Although angles high 0.1° are recorded, reciprocal space mapping (RSM) broadening and wafer bow measurements do not show any significant changes function angle. While tilting shown be effective controlling strain some other systems, it does provide appreciable relief compressive AlGaN/AlN heteroepitaxy.