Unpinned Interface Between Al_20_3 Gate Dielectric Layer Grown by Atomic Layer Deposition and Chemically Treated n-In_(0.53)Ga_(0.47)As ( 001)

摘要

An unpinned interface between an Al_2O_3 layer deposited by atomic layer deposition (ALD) and a chemically treated n-In_(0.53)Ga_(0.47)As(001) is demonstrated. The starting surface was prepared by wet etching with NH_4OH(aq) followed by a thermal desorption of residual As at 380℃ immediately before ALD. Analysis of temperature-dependent capacitance_voltage measurements suggests that the Fermi level can sweep through the bandgap of In_(0.53)Ga_(0.47)As, attaining true accumulation and inversion despite the presence of In oxide and In hydroxide at the interface. This is in contrast to the situation for residual As-related interfacial species, which have been reported to pin the Fermi level at oxide/III_V interfaces.