Electrical characterization of MIS diode prepared by magnetron sputtering
TiO2 thin film has been prepared on n-type Si wafer to fabricate an Au/TiO2/n-Si (MIS) diode by RF magnetron sputtering technique. The current-voltage (I-V) and capacitance-voltage (C-V) measurements of the diode have been performed over a wide range of temperatures (240-400 K) and frequencies (10 kHz-1 MHz), respectively. From I-V measurements, an abnormal increase in the barrier height (Φb) and a decrease in the ideality factor (n) with increasing temperature have been observed. This temperature dependence has been attributed to the barrier in homogeneities by assuming a Gaussian distribution (GD) of barrier heights at metal/semiconductor (M/S) interface. Both the conventional and modified Richardson plot show linearity. The activation energy (Ea), Richardson constant (A*) and Φb value have been calculated from the slope and intercept of the linear region. The obtained Richardson constant value of 113.82 A. cm-2. K-2 is in close agreement with the known value of 112 A.cm-2. K-2 for n-Si. The interface state density (Nss) and series resistance (Rs) of the diode has been obtained from the I-V measurements. In addition, the Φb value was determined from C-2-V characteristics. The obtained results indicate that the MIS diode with TiO2 interfacial insulator layer can be used in many device applications.
MIS diode; TiO2 thin film; Ideality factor; Barrier height; Interface states; Series resistance
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