Temperature-dependent characteristics of Tantalum and Tantalum nitride based p-Si structures

Abstract

We investigated the temperature-dependent current-voltage (I-V-T) characteristics data of Ta and Ta/TaN-based p-Si Schottky barrier diodes (SBDs). The Schottky barrier heights (SBH) for Ta/p-Si and Ta/TaN_1-x/p-Si SBDs were obtained as 0.574 eV and 0.717 eV at 300 K, respectively. The difference between their SBHs is 0.143 eV at 300 K. At temperatures below 240 K for the Ta/TaN_1-x/p-Si, more excess current than estimated by the TE model was observed at low bias voltages in the I-V curves. The excess current increased with a decrease in temperature. The phenomenon has been ascribed to the low SBH-patches embedded at the MS interface. Moreover, the thermal sensitivity V-T data were measured from 20 K up to 320 K at 2.0 K intervals under different current levels. It has been seen that the linear portion of the V-T traces of the Ta/TaN_1-x/p-Si SBDs have corresponded to a wider temperature range with more thermal sensitivity coefficient α than that of the Ta/p-Si at each current level. For example, the α values of 2.573 and 2.710 mV/K at 50 nA, and 2.070 and 2.230 mV/K at 10.0 μA have been obtained for the Ta/p-Si and Ta/TaN_1-x/p-Si SBDs, respectively.