Temperature Dependent Current-Voltage Characteristics of n-Type β-FeSi2/Intrinsic Si/p-Type Si Heterojunctions

In this work, n-type β-FeSi2/intrinsic Si/p-type Si heterojunctions were prepared by facing-targets direct-current sputtering. We measured their current-voltage characteristics at low temperatures ranging from 300 K down to 50 K and investigated their ideality factor, saturation current and series resistance using thermionic emission theory and Cheung’s method. From thermionic emission theory, the ideality factor and saturation current density were calculated from the slope of the linear part from the forward lnJ-V and the straight line intercept of lnJ-V at zero voltage, respectively. When the temperature decreased from 300 K down to 50 K, the ideality factor increased from 1.12 to 11.13, whereas the saturation current density decreased from 2.09 × 10-6 A/cm2 to 1.06 × 10-9 A/cm2. Using Cheung’s method, we plotted the relations of dV/d(lnJ)-J and H(J)-J in order to estimate the series resistance from the slope of both plots. In addition, we estimated the ideality factor from a y-axis intercept of the dV/d(lnJ)-J plot. The series resistances from both plots were consistent with each other and increased with the decreasing temperature. The ideality factor estimated by Cheung’s method was in agreement with that obtained from estimation by thermionic emission theory.