Photoemission spectroscopy has been used to observe the interface electronic states as HfO_(2) was deposited on clean n-type Ga-face GaN (0001) surfaces. The HfO_(2) was formed by repeated deposition of several monolayers of Hf followed by remote plasma oxidation at 300℃, and a 650℃ densification anneal. The 650℃ anneal resulted in a 0.6 and 0.4 eV change in band bending and valence band offset, respectively. The final annealed GaN/HfO_(2) 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.
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