Achieving a low interfacial density of states in atomic layer deposited Al2 O3 on In0.53 Ga0.47 As
Journal
Applied Physics Letters
Journal Volume
93
Journal Issue
20
Date Issued
2008
Author(s)
Abstract
Atomic-layer-deposited Al2O3 on In0.53Ga0.47As with short air exposure between the oxide and semiconductor deposition has enabled the demonstration of nearly ideal frequency-dependent and quasistatic capacitance-voltage (C-V) characteristics. The excellent quasistatic C-V characteristics indicate a high efficiency of 63% for the Fermi-level movement near the midgap. A low mean interfacial density of states (D¯it)∼2.5×1011 cm−2 eV−1 was determined under 1 MHz using a charge pumping method, which was also employed to probe the depth profile of bulk traps (Nbt) and the energy dependence of Dit at 50 kHz: a low Nbt∼7×1018 cm−3 and a Dit of (2–4)×1011 cm−2 eV−1 in the lower half of the band gap and a higher Dit of ∼1012 cm−2 eV−1 in the upper half of the band gap. The employment of charge pumping method has given a more accurate determination of Dit, which is usually overestimated using other commonly methods such as the Terman, conductance, and high-low frequencies due to the influence of weak inversion at room temperature.
SDGs
Type
journal article