TEMPERATURE-DEPENDENCE OF THE ELECTRICAL CHARACTERISTICS OF YB/P-INP TUNNEL METAL-INSULATOR-SEMICONDUCTOR JUNCTIONS

High barrier Yb/p-InP metal-insulator-semiconductor (MIS) and metal-semiconductor (MS) junctions were fabricated by evaporation of Yb on InP:Zn substrates. The capacitance-voltage (C-V) and current-voltage (I-V) characteristics of these devices were measured over a wide range of temperatures. From the room-temperature forward I-V data, the values of 1.06 and 1.30 for the ideality factor (n) were obtained for the MIS and MS diodes, respectively. The higher value of n was attributed to an order of magnitude higher density of interface states in the MS junction than in the MIS diodes. The I-V/T data over the temperature range 190-400 K, indicated that the forward current transport in the Yb/p-InP MIS junction was controlled by the thermionic-field emission (TFE) mechanism. The analysis of the reverse saturation current I0 in terms of the TFE model provided a value of 1.07±0.03 V for the zero bias, zero temperature barrier height (φ0) which was in close agreement with the value of φ0=1.03±0.04 V, provided by the C-V data. For the MS diode, the temperature dependence of the forward I-V characteristics over the temperature range 250-350 K were well described by the thermionic emission process. However, the value of φ0=0.80±0.04 V, determined from the I-V data was much smaller than the value of φ0=0. 96±0.04 V, obtained from the C-V data.