We report experimental and theoretical studies of defects producing fixed charge within Al(2)O(3) layers grown by atomic layer deposition (ALD) on In(0.53)Ga(0.47)As(001) substrates and the effects of hydrogen passivation of these defects. Capacitance-voltage measurements of Pt/ALD-Al(2)O(3)/n-In(0.53)Ga(0.47)As suggested the presence of positive bulk fixed charge and negative interfacial fixed charge within ALD-Al(2)O(3). We identified oxygen and aluminum dangling bonds (DBs) as the origin of the fixed charge. First-principles calculations predicted possible passivation of both O and Al DBs, which would neutralize fixed charge, and this prediction was confirmed experimentally; postmetallization forming gas anneal removed most of the fixed charge in ALD-Al(2)O(3). (C) 2010 American Institute of Physics. (doi:10.1063/1.3399776

Brammertz, G.; Heyns, M.; Newcomb, Simon B.; Afanas'ev, V. V.;Hurley, Paul K.

The literature on polar Gallium Nitride (GaN) surfaces, surface treatments and gate dielectrics relevant to metal oxide semiconductor devices is reviewed. The significance of the GaN growth technique and growth parameters on the properties of GaN epilayers, the ability to modify GaN surface properties using in situ and ex situ processes and progress on the understanding and performance of GaN metal oxide semiconductor (MOS) devices are presented and discussed. Although a reasonably consistent picture is emerging from focused studies on issues covered in each of these topics, future research can achieve a better understanding of the critical oxide-semiconductor interface by probing the connections between these topics. The challenges in analyzing defect concentrations and energies in GaN MOS gate stacks are discussed. Promising gate dielectric deposition techniques such as atomic layer deposition, which is already accepted by the semiconductor industry for silicon CMOS device fabrication, coupled with more advanced physical and electrical characterization methods will likely accelerate the pace of learning required to develop future GaN-based MOS technology.

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