The distribution of barrier heights in MIS type Schottky diodes from current-voltage-temperature (I-V-T) measurements


TATAROĞLU A. , ALTINDAL Ş.

JOURNAL OF ALLOYS AND COMPOUNDS, cilt.479, ss.893-897, 2009 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 479
  • Basım Tarihi: 2009
  • Doi Numarası: 10.1016/j.jallcom.2009.01.098
  • Dergi Adı: JOURNAL OF ALLOYS AND COMPOUNDS
  • Sayfa Sayıları: ss.893-897

Özet

The forward bias current-voltage-temperature (I-V-T) characteristics of the Au/SiO2/n-Si (MIS) type Schottky diodes (SDs) have been investigated in the temperature range of 300-400 K. The estimated zero-bias barrier height (Phi(B0)) and the ideality factor (n) assuming thermionic emission (TE) theory show strong temperature dependence. An abnormal decrease in the Phi(BO) and an increase in the n with decreasing temperature have been explained on the basis of the TE theory with a Gaussian distribution (GD) of the barrier heights (BHs) due to BH inhomogeneities. The conventional Richardson plot should be a straight line especially at intermediate temperatures (T <= 325). The values of activation energy (E-a) and Richardson constant (A*) were determined as 0.167 eV and 1.385 x 10(-6) A cm(-2) K-2 from the slope and the intercept at ordinate of the linear region of this plot, respectively. Also, we attempted to draw a Phi(B0) versus q/2kT plot in order to obtain evidence of the GD of BHs, and the values of (Phi) over bar (B0) = 1.301 eV and sigma(s) = 0.187 V for the mean barrier height and zero-bias standard deviation have been obtained from this plot. respectively; then, a modified In(I-0/T-2) - q(2)sigma(2)(s)/2k(2)T(2) versus q/kT plot gives (Phi) over bar (B0) and A* as 1.298 eV and 109.481 A cm(-2) K-2, respectively. This value of the A* (=109.481 A cm(-2) K-2) is very close to the theoretical value of 112 A cm(-2) K-2 for n-type Si. Therefore, it has been concluded that the temperature dependence of the forward bias I-V characteristics of the MIS type Schottky diodes can be successfully explained on the basis of TE mechanism with a GD of the BHs. (c) 2009 Elsevier B.V. All rights reserved.