Electrical characteristics of Au/p-AlSb metal-insulator-semiconductor Schottky diodes

Metal-insulator-semiconductor Schottky barrier diodes have been prepared on p-type bulk AlSb by evaporating gold on a chemically etched (100) AlSb surface. The existence of an oxide-rich interfacial layer between gold and AlSb of ∼70 Å thickness was shown by means of secondary ion mass spectrometry analysis. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics were measured. The barrier height qφ_Bp(0) obtained from the Richardson plot log(I_s/T²) vs (1/nT) is 0.71 eV. The 1/C²-vs-V plot was not a straight line. From the ideality factor at room temperature (n=1.4) and the intercept voltage V₀ of the 1/C²-vs-V curve (V₀=1.2 V), a density D_s of interface states was evaluated around 5×10¹¹ cm^-2 eV^-1.