The effect of Schottky metal thickness on barrier height inhomogeneity in identically prepared Au/n-GaAs Schottky diodes

Abstract

We have studied identically prepared Au(5 nm)/n-GaAs (35 dots) and Au(65 nm)/n-GaAs (38 dots) Schottky barrier diodes (SBDs) on the same n-type GaAs single crystal. A GaAs wafer has been prepared by the usual chemical etching, and evaporation of the metal has been carried out in a conventional vacuum system. The effective Schottky barrier heights (SBHs) and ideality factors obtained from the current–voltage (I–V) characteristics have differed from diode to diode. The SBH for the Au(5 nm)/n-GaAs diodes have ranged from 0.839 to 0.943 eV and the ideality factor n from 1.011 to 1.150. The SBH for the Au(65 nm)/n-GaAs diodes have ranged from 0.828 to 0.848 eV and the ideality factor n from 1.026 to 1.069. Our aim is to find the laterally homogeneous SBH values of the SBDs depending on Schottky metal thickness. The lateral homogeneous SBH values of 0.940 eV for the Au(5 nm)/n-GaAs and 0.866 eV for the Au(65 nm)/n-GaAs diodes have been calculated from a linear relationship between barrier height (BH) and the ideality factor, which can be explained by lateral inhomogeneities of the SBH, respectively.