Nonlinear analysis of the I-V characteristics in Ti/Si and TiSi2/Si Schottky diodes

Ti/Si and TiSi2/Si diodes have been prepared by direct current (de) sputtering and rapid thermal processing. Their I-V characteristics from 77 K up to 300 K have been analyzed using a nonlinear least squares method to fit the experimental data. All the experimental data have been fitted using two exponentially dependent currents and a series resistance. Two parameters are fitted for each current: a saturation current and an exponential parameter. As is discussed in the article, one current can be assigned to the thermoionic current, since the exponential parameter fits well to the theoretical value q/kT and therefore a temperature independent Schottky barrier height can be calculated. The second current, which yields an exponential parameter independent of temperature, cannot be assigned to a mechanism of direct tunneling through the barrier. As a result, we have proposed a trap-enhanced tunneling mechanism to explain this current. (C) 1996 American Vacuum Society.