Characterizations of laser-assisted debonded GaN films

Detailed I-V, photoluminescence and low-frequency noise were measured on devices fabricated on GaN-on-Si films obtained by layer transfer of laser-debonded hydride vapor phase epitaxy (HVPE)-grown GaN films onto Si substrates. The experimental data demonstrate significant reduction of localized states at the metal-semiconductor interface compared to the control devices fabricated on GaN-on-sapphire films. However, experiments performed to investigate the bulk of the films yielded contradictory results. It is proposed that GaN material close to sapphire-GaN interface suffers material degradation due to the extreme local temperature rise during the debonding process. Away from the interface, the temperature rise was substantially reduced and some annealing effect may take place leading to the reduction of defects in the material.