Evolution Of Traps In Tin/O-3-Sourced Al2o3/Gan Gate Structures With Thermal Annealing Temperature

The interface between a GaN epitaxial layer and an Al2O3 gate dielectric, which was grown by atomic layer deposition using O-3 as the oxygen source on top of a 2-nm H2O-sourced Al2O3 interfacial layer, was engineered by applying a high-temperature postmetal annealing (PMA) process. The O-3-sourced Al2O3 gate dielectric featured good thermal stability and breakdown behavior, even at a PMA temperature of 700 degrees C. Moreover, deep interface/bulk traps in the O3-sourced Al2O3/GaN structures were effectively suppressed, as confirmed by characterization using deep-level transient spectroscopy. However, extended line defects and holelike traps were observed at higher PMA temperatures (750 degrees C), which were considered to originate from the interface reaction between partially crystallized O-3-sourced Al2O3 and the GaN epitaxial layer. Published by the AVS.