Temperature dependence of forward and reverse bias current-voltage characteristics in Al-TiW-PtSi/n-Si Schottky barrier diodes with the amorphous diffusion barrier


Afandiyeva I. M. , Demirezen S., Altindal Ş.

JOURNAL OF ALLOYS AND COMPOUNDS, vol.552, pp.423-429, 2013 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 552
  • Publication Date: 2013
  • Doi Number: 10.1016/j.jallcom.2012.11.093
  • Title of Journal : JOURNAL OF ALLOYS AND COMPOUNDS
  • Page Numbers: pp.423-429

Abstract

The forward and reverse bias current-voltage (I-V) characteristics of Al-TiW-PtSi/n-Si SBDs which are fabricated by a magnetron sputtering method, were measured in the temperature and applied bias voltage ranges of 80-360 K and (-25)-(5) V, respectively. The diode matrix contains 14 Al-TiW-PtSi/n-Si diodes with the rectifier contact areas between 1 x 10 (6) cm(2) and 14 x 10 (6) cm(2). It was found that the ideality factor n decreases, while the zero-bias Schottky barrier height (Phi(B0)) increases with increasing temperature. The conventional Richardson plot was also found to be nonlinear especially at low temperatures. Therefore, Phi(B0) vs. q/kT plot was drawn to obtain an evidence of a Gaussian Distribution (GD) of barrier heights (BHs), and mean BH and zero-bias standard deviation values were obtained from this plot as (Phi) over bar (B) = 0.856 eV and sigma(0) = 95 mV, respectively. Thus, a modified ln(I-0/T-2) - (q(2)sigma(2)(0))/2k(2)T(2) vs. q/kT plot gives (Phi) over bar (B) and the Richardson constant (A*) as 0.820 eV and 169 Acm K-2 (2), respectively. On the basis of obtained results, it can be concluded that the hexagonal emptiness in crystal lattice of Si(1 1 1) strongly influence the electric parameters of Al-TiW-PtSi/n-Si structures and its I-V characteristics can be successfully explained on the basis of a thermionic emission (TE) mechanism with Gaussian distribution (GD) of the barrier heights (BHs). The crossing of the experimental semi-logarithmic reverse bias ln I-V plots appears as an abnormality considering the conventional behavior of ideal SBDs. This behavior could be expected for semiconductors in the temperature region where there is no carrier freezing-out which is non-negligible at low temperatures. (C) 2012 Elsevier B.V. All rights reserved.