Abstract
We have investigated the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the Pt/Ti Schottky contacts
on n-type InP in the temperature range of 200-440 K. An experimental barrier height (BH) Φbo and ideality factor n values of
0.47 eV (I-V), 0.82 eV (C-V) and 3.26, and 0.74 eV (I-V), 0.73 eV (C-V) and 1.21 are obtained for the Pt/Ti/n-InP Schottky
diode at 200 K and 440 K.. A decrease in the experimental BH Φbo and an increase in the ideality factor n with a decrease in
temperature have been explained on the basis of a thermionic emission (TE) mechanism. This behaviour is interpreted by
the assumption of Gaussian distribution of the barrier heights due to the barrier inhomogeneities that prevail at the metalsemiconductor
interface. It is found that the series resistance (Rs) of Pt/Ti Schottky contacts is strongly temperature
dependent. A modified ln(Io/T2)-q2σo
2/2(kT)2 versus 1000/T plot gives mean barrier height bO and Richardson constant A*
as 0.94 eV and 6.23 A/cm2K2, respectively. The Richardson constant value of 6.23 A/cm2K2 is in close agreement with the
known value of 9.4 A/cm2K2 for n-type InP. The discrepancy between Schottky barrier heights (SBHs) calculated from I-V
and C-V measurements is also explained. It can be concluded that the temperature dependent characteristics of the Pt/Ti/n-
InP Schottky diode can be explained on the basis of thermionic emission (TE) mechanism with Gaussian distribution of the
Schottky barrier heights (SBHs)..
Keywords
Pt/Ti Schottky contacts, Temperature dependent electrical properties, Barrier inhomogeneities, Gaussian distribution,
Thermionic emission.
Citation
D. SUBBA REDDY, M. SIVA PRATAP REDDY, V. RAJAGOPAL REDDY, Analysis of current-voltage-temperature (I-V-T) and capacitance-voltage-temperature (C-V-T) characteristics of Pt/Ti Schottky contacts on n-type InP, Optoelectronics and Advanced Materials - Rapid Communications, 5, 4, April 2011, pp.448-454 (2011).
Submitted at: March 31, 2011
Accepted at: April 11, 2011