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Impact of native defects in high‐k dielectric oxides on GaN/oxide metal–oxide–semiconductor devices
Author(s) -
Choi Minseok,
Lyons John L.,
Janotti Anderson,
Van de Walle Chris G.
Publication year - 2013
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201200628
Subject(s) - materials science , optoelectronics , oxide , band gap , dielectric , fermi level , semiconductor , leakage (economics) , transistor , valence (chemistry) , condensed matter physics , chemistry , electrical engineering , voltage , physics , electron , organic chemistry , quantum mechanics , economics , metallurgy , macroeconomics , engineering
We perform first‐principles calculations to investigate the electronic structure of native defects in various oxide dielectrics to address the impact of defects on GaN/oxide metal–oxide–semiconductor (MOS) devices. We calculate defect formation energies in Al 2 O 3 , HfO 2 , and LaAlO 3 , as a function of the chemical potentials and of the Fermi‐level position in the band gap. By aligning the conduction‐band and valence‐band edges of these oxides to those of GaN, the role of native defect as charge‐trap or fixed‐charge centers in GaN‐based MOS devices is examined. We find that oxygen vacancies in the oxide dielectrics result in charge‐state transition levels near the GaN conduction‐band edge. They can therefore introduce border traps and/or leakage current through the gate dielectric in the n‐GaN/oxide MOS devices such as MOS field‐effect‐transistors. While the transition levels for other defects are well away from the GaN conduction‐band edge, these defects are stable in non‐neutral charge states and thus act as sources of fixed charge in MOS devices.