Barrier characteristics of [formula omitted] Schottky diodes as determined from I- V- T measurements

Abstract

The current-voltage-temperature characteristics of PtSi/p-Si Schottky barrier diodes were measured in the temperature range 60–115 K. Deviation of the ideality factor from unity below 80 K may be modelled using the so-called T 0 parameter with T 0 = 18 K. It is also shown that the curvature in the Richardson plots may be remedied by using the flatband rather than the zero-bias saturation current density. Physically, the departure from ideality is interpreted in terms of an inhomogeneous Schottky contact. Here we determine a mean barrier height at T = 0 K, ƒ b 0 = 223 mV , with an (assumed) Gaussian distribution of standard deviation σ ƒ = 12.5 mV . These data are correlated with the zero-bias barrier height, ƒ j 0 = 192 mV (at T = 90 K), the photoresponse barrier height, ƒ ph = 205 mV , and the flatband barrier height, ƒ fb = 214 mV . Finally, the temperature coefficient of the flatband barrier was found to be −0.121 mVK −1, which is approximately equal to 1 2 (dE g i/dT) , thus suggesting that the Fermi level at the interface is pinned to the middle of the band gap.