Fermi level unpinning of GaSb (100) using plasma enhanced atomic layer deposition of Al2 O3

A. Ali, H. S. Madan, A. P. Kirk, D. A. Zhao, D. A. Mourey, M. K. Hudait, R. M. Wallace, T. N. Jackson, B. R. Bennett, J. B. Boos, S. Datta

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Abstract

N-type and p-type GaSb metal-oxide-semiconductor capacitors (MOSCAPs) with atomic-layer-deposited (ALD) and plasma-enhanced-ALD (PEALD) Al2 O3 dielectrics are studied to identify the optimum surface preparation and oxide deposition conditions for a high quality oxide-semiconductor interface. The ALD Al2 O3 /GaSb MOSCAPs exhibit strongly pinned C-V characteristics with high interface state density (Dit) whereas the PEALD Al2 O3 /GaSb MOSCAPs show unpinned C-V characteristics (low Dit). The reduction in Sb2 O 3 to metallic Sb is suppressed for the PEALD samples due to lower process temperature, identified by x-ray photoelectron spectroscopy analysis. Absence of elemental Sb is attributed to unpinning of Fermi level at the PEALD Al2 O3 /GaSb interface.

Original languageEnglish (US)
Article number143502
JournalApplied Physics Letters
Volume97
Issue number14
DOIs
StatePublished - Oct 4 2010

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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