Selective layer disordering in intersubband Al_(0.028)Ga_(0.972)N/AlN superlattices with silicon nitride capping layer

摘要

Selective layer disordering in an intersubband Al_(0.028)Ga_(0.972)N/AlN superlattice using a silicon nitride (SiN_x) capping layer is demonstrated. The SiN_x capped superlattice exhibits suppressed layer disordering under high-temperature annealing. Additionally, the rate of layer disordering is reduced with increased SiN_x thickness. The layer disordering is caused by Si diffusion, and the SiN_x layer inhibits vacancy formation at the crystal surface and ultimately, the movement of Al and Ga atoms across the heterointerfaces. Patterning of the SiN_x layer results in selective layer disordering, an attractive method to integrate active and passive Ⅲ-nitride-based intersubband devices.