Band offset measurements of the GaN/dielectric interfaces

X-ray and ultra violet photoelectron spectroscopy are used to observe the interface electronic states at the GaN (0001) and high-κ dielectric interfaces. The GaN is aqueous HCl cleaned prior to atomic layer deposition of Al2O3 and HfO2, then followed by a post deposition anneal. The GaN/HfO2 and GaN/Al2O3 interfaces exhibited dipoles of 1.6 eV and 0.4 eV, respectively. It is found that the formation of an interfacial layer at the GaN/HfO2 interface is the primary cause of the larger dipole.