Analysis of trap state densities at HfO2/In0.53Ga0.47As interfaces

HfO 2 was deposited on n- and p-type In0.53Ga0.47As by chemical beam deposition. Interface trap densities (Dit) and their energy level distribution were quantified using the conductance method in a wide temperature range (77 to 300 K). A trap level close to the intrinsic energy level caused the Dit to rise above 1013 cm−2 eV−1. The trap level at midgap gives rise to false inversion behavior in the capacitance-voltage curves for n-type channels at room temperature. The apparent decrease of the Dit close to the band edges is discussed.