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.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)