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

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2016-01-01

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Mcode

Degree programme

Language

en

Pages

7
1-7

Series

AIP ADVANCES, Volume 6, issue 1

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.

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Keywords

N-type GaN, leakage current, Cu2O films, temperature, semiconductor, contacts, epitaxy, copper, hemt

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Citation

Garg, M, Kumar, A, S., N, Sopanen, M & Singh, R 2016, ' Investigation of significantly high barrier height in Cu/GaN Schottky diode ', AIP Advances, vol. 6, no. 1, 015206, pp. 1-7 . https://doi.org/10.1063/1.4939936