The distribution of barrier heights in Au/n-Si Schottky barrier diodes from I-V-T measurements


Durmus P., Cuha B., Altindal Ş. , AYDEMİR U.

OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS, vol.4, no.4, pp.579-583, 2010 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 4 Issue: 4
  • Publication Date: 2010
  • Title of Journal : OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS
  • Page Numbers: pp.579-583

Abstract

The forward bias current-voltage (I-V) characteristics of Au-/n-Si(111) Shottky barrier diodes (SBDs) with native interfacial insulator layer have been investigated in the wide temperature range of 80-400 K. Their analysis on the basis of the standard thermionic emission (TE) mechanism reveals an abnormal decrease of the zero-bias barrier height (Phi(B)) and increase of ideality factor (n) with decrease in temperature and nonlinearity in the activation energy plot. Such behavior of Phi(B0) and n are attributed the barrier inhomogeneities by assuming a Gaussian distribution (GD) of barrier heights (BHs) at metal/semiconductor (M/S) interface. The experimental Phi(B) vs q/2kT plot show that an existence of a double GD having mean BHs and standard deviations 0.747 eV and 0,081 V (between 80 and 200 K) and 1.203 eV and 0.146 V (between 230 and 400 K), respectively. Thus, the modified ln(I-o/T-2)-q(2) sigma(2)(o)/2k(2)T(2) vs q/kT plot gives Phi(B) and A* as 0.682 eV and 3.14 A cm(-2) K-2 (between 80 and 200 K) and 1.199 eV and 110.16 A cm(-2) K-2 (between 230 and 400 K), respectively, without using the temperature coefficient of the BH. This value of the Richardson constant 110.16 A/cm(2)K(2) is close to the theoretical value of 120 A K-2 cm(-2) for n-type Si. Hence, it has been concluded that the temperature dependence of the forward bias I-V characteristics of the Au-/n-Si(111) SBDs can be successfully explained on the basis of TE mechanism with a double GD of the BHs.