On the electrical characteristics of Au/n-type GaAs Schottky diode

• Electrical properties are analyzed by considering inhomogeneous SBH at the SD.
• SBH inhomogeneities are attributed to defects that are located at GaAs surface.
• Thermionic field emission is the dominant transport mechanism at low temperature.

The temperature dependence of the electrical properties of Au/n-type GaAs Schottky contacts have been studied using current–voltage (I–V) and capacitance–voltage (C–V) over a wide temperature range 100–300 K. In the low temperature range 100–140 K, the absence of temperature dependent tunneling parameters has been explained in terms of thermionic field emission. In the high temperature range 140–300 K, the zero-bias barrier height (Φ0bn) was found to decrease and the ideality factor (n) to increase with decreasing temperature. This abnormal temperature dependence of Φ0bn and n is interpreted on the basis of a thermionic emission mechanism by considering the existence of the barrier height inhomogeneities (BHi) at the metal/GaAs interface. From the linear plot of the experimental Schottky barrier height (SBH) vs. 1/T based on the BHi   model, the value of the homogeneous SBH (Φ‾0bn) of 1.03 eV and a zero-bias standard deviation (σ0s) of 89 meV were computed. Furthermore the modified Richardson plot according to the Gaussian distribution model resulted in a homogeneous SBH (Φ‾0bn) of 1.02 eV and a Richardson constant (A*) of 7.97 A/cm2 K2, respectively. The value of A* obtained from this plot is in very close agreement with the theoretical reported value of 8.16 A/cm2 K2 for n-type GaAs.