Double Gaussian distribution of barrier height for FeCrNiC alloy Schottky contacts on p-Si substrates

The electrical properties of Schottky contact with a quadripartite alloy FeCrNiC on p-Si have been investigated in the temperature range of 80-320K, for the first time. An abnormal decrease in the apparent barrier height (phi(ap.)) and an increase in the apparent ideality factor (n(ap.)) with a decrease in the temperature were elucidated by the current-voltage (I-V) characteristic of the FeCrNiC/p-Si structure. The conventional Richardson plot exhibits non-linear behaviour at temperature below 180K with the linear portion to be used for the calculation of activation energy and Richardson constant (A*) as 0.352 eV and 8.3 x 10(-3) AK(-2) CM-2, respectively. The observed anomalies were explained on the basis of the thermionic emission (TE) theory by incorporating the concept of inhomogeneous multiple barriers at Metal-Semiconductor (MS) interface. It has been seen that the apparent barrier height phi(ap.) exhibits double Gaussian distribution (DGD) feature with the mean BH (75bp) of 0.695 and 0.646 eV, accompanied by their standard deviations (0-0) of 0.082 and 0.070 eV in 320-180K and 180-80K regions, respectively. These values of the Om have been confirmed with the modified Richardson plot [1n(J(0)/T-2) - (q(2)sigma(0)2k(2)T(2)) vs. 1/T] as 0.690 eV and 0.633 eV at the demarcated temperature regions, respectively. Richardson constant A* has also been calculated from the modified Richardson plots as 33.43 AK(-2) cm(-2) and 28.47 AK(-2) cm(-2) that belong to two distinct temperature ranges. Their average value exactly matched the theoretical value of 31.6 AK(-2) CM-2 for the holes in p-type Si. Our results confirm the predictions of the multiple GD approach of nanoscale spatial BH inhomogeneities at the MS interface. (C) 2014 Elsevier B.V. All rights reserved.