Achieving a low interfacial density of states in atomic layer deposited Al2O3 on In0.53Ga0.47As

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)over bar(it))similar to 2.5x10(11) 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 (N-bt) and the energy dependence of D-it at 50 kHz: a low N-bt similar to 7x10(18) cm(-3) and a D-it of (2-4)x10(11) cm(-2) eV(-1) in the lower half of the band gap and a higher D-it of similar to 10(12) 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 D-it, 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.