Characterization of interface states and investigation of possible current conduction mechanisms in the Pt, Au, Cu/n-InP Schottky diodes

Based on the capacitance/conductance-voltage (C/G-V) and current-voltage (I-V) methods, the interface characteristics and the current conduction mechanisms of Pt/n-InP Schottky contacts were studied in detail. The interface states strongly affected the values of capacitance in the depletion region. From Terman, G-V, and forward I-V methods, the interface state density (D _it) was found to range from mid-10¹² to mid-10¹³ eV⁻¹cm⁻². The forward current characteristics was not elucidated by the thermionic emission (TE) model assisted by tunneling via the interfacial layer. Rather, the spatially distributed inhomogeneous barrier could interpret the forward current characteristics. Trap-assisted tunneling involving phosphorous vacancy (V_P)-related defects was observed to be dominant in the case of the reverse current characteristics. The comparison of Pt metal contact with Cu and Au contacts revealed that Pt contact has the highest D _it among three contacts.