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.

Schottky Barriers on Layered Anisotropic Semiconductor – WSe<sub>2</sub> – with 1000 Å Indium Metal Thickness

“…The higher value of 0 b  indicates a more homogeneous diode, which is supported by the percentage of inhomogeneity values. Similar results on metal thickness studies were reported in Au/n-GaAs Schottky diodes also [30].…”

Schottky diode characteristics: Aluminium with 500 and 1000 Å thicknesses on p type WSe2 crystal

“…On the other hand, the value of standard deviation is less for 500 Å diode compared to 1000 Å diode. Biber et al [34] has reported similar results in Au/n-GaAs Schottky diodes. The higher value of activation energy with minimum standard deviation is an indication of transition of charges from valence band to conduction band mainly by direct mechanism.…”

Analysis of inhomogeneous device parameters using current–voltage characteristics of identically prepared lateral Schottky structures

“…The calculated values of the ideality factors and barrier heights from I to V measurements differ from diode to diode although the diodes are identically prepared. Therefore, the common practice is to take the average [27][28][29] and the standard deviations of the macroscopic barrier heights derived from the Gaussian distributions, which should be called the standard error [30]. Gaussian function is used to fit the calculated n and U B values.…”