Band offset measurements of the GaN (0001)/HfO2 interface

Photoemission spectroscopy has been used to observe the interface electronic states as HfO2 was deposited on clean n-type Ga-face GaN (0001) surfaces. The HfO2 was formed by repeated deposition of several monolayers of Hf followed by remote plasma oxidation at 300degreesC, and a 650degreesC densification anneal. The 650degreesC anneal resulted in a 0.6 and 0.4 eV change in band bending and valence band offset, respectively. The final annealed GaN/HfO2 interface exhibited a valence band offset of 0.3 eV and a conduction band offset of 2.1 eV. A 2.0 eV deviation was found from the electron affinity band offset model. (C) 2003 American Institute of Physics.