Investigation of significantly high barrier height in Cu/GaN Schottky diode

S Nagarajan,Ashutosh Kumar,M Sopanen,Manjari Garg,R Singh

doi:10.1063/1.4939936

S Nagarajan, Ashutosh Kumar + Show 3 more

Open Access

https://doi.org/10.1063/1.4939936

Copy DOI

Abstract

Current-voltage (I-V) measurements combined with analytical calculations have been used to explain mechanisms for forward-bias current flow in Copper (Cu) Schottky diodes fabricated on Gallium Nitride (GaN) epitaxial films. An ideality factor of 1.7 was found at room temperature (RT), which indicated deviation from thermionic emission (TE) mechanism for current flow in the Schottky diode. Instead the current transport was better explained using the thermionic field-emission (TFE) mechanism. A high barrier height of 1.19 eV was obtained at room temperature. X-ray photoelectron spectroscopy (XPS) was used to investigate the plausible reason for observing Schottky barrier height (SBH) that is significantly higher than as predicted by the Schottky-Mott model for Cu/GaN diodes. XPS measurements revealed the presence of an ultrathin cuprous oxide (Cu2O) layer at the interface between Cu and GaN. With Cu2O acting as a degenerate p-type semiconductor with high work function of 5.36 eV, a high barrier height of 1.19 eV is obtained for the Cu/Cu2O/GaN Schottky diode. Moreover, the ideality factor and barrier height were found to be temperature dependent, implying spatial inhomogeneity of barrier height at the metal semiconductor interface.

Highlights

Group III-Nitride based electronic devices have seen a strong growth in interest and application over the past two decades due to their unique properties
Current-voltage (I-V) measurements combined with analytical calculations have been used to explain mechanisms for forward-bias current flow in Copper (Cu) Schottky diodes fabricated on Gallium Nitride (GaN) epitaxial films
It can be seen that the current rectification at ±2V is of the order of 108 in the temperature range of 240-340 K, but the rectification decreases with the decrease in

Summary

Introduction

Group III-Nitride based electronic devices have seen a strong growth in interest and application over the past two decades due to their unique properties. Investigation of significantly high barrier height in Cu/GaN Schottky diode An ideality factor of 1.7 was found at room temperature (RT), which indicated deviation from thermionic emission (TE) mechanism for current flow in the Schottky diode.

Results

Conclusion