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

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

Research output: Contribution to journalArticleScientificpeer-review

21 Citations (Scopus)
295 Downloads (Pure)

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.

Original languageEnglish
Article number015206
Pages (from-to)1-7
Number of pages7
JournalAIP ADVANCES
Volume6
Issue number1
DOIs
Publication statusPublished - 1 Jan 2016
MoE publication typeA1 Journal article-refereed

Keywords

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

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