GaN cleaning by Ga deposition, reduction and re-evaporation: An SXPS study

T. G.G. Maffeis*, S. A. Clark, P. R. Dunstan, S. P. Wilks, D. A. Evans, F. Peiro, H. Riechert, P. J. Parbrook

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (SciVal)

Abstract

The Ga deposition, reduction, and re-evaporation technique commonly used to produce clean n-GaN surfaces and Ag-GaN interface formation on the resultant surface, have been investigated by Soft X-ray Photoelectron Spectroscopy (SXPS) and current-voltage measurements. SXPS studies have indicated that Ga deposition produces a band-bending of ΔEk = +1.0 eV to higher kinetic energy. Our results show this shift to be a partially reversible process: re-evaporation of the deposited Ga resulted in a Fermi shift of ΔEk = -0.6 eV to lower energy. Ag deposition did not cause any further Fermi shift, indicating that the Fermi level is pinned (2.2±0.2) eV above the valence band edge, possibly as a consequence of the cleaning procedure itself. Current voltage (I-V) measurements have shown a barrier height of 0.77 eV and an ideality factor of 1.6. Metal induced gap states and the unified defect model are discussed as possible barrier formation mechanisms.

Original languageEnglish
Pages (from-to)751-754
Number of pages4
JournalPhysica Status Solidi (A) Applied Research
Volume176
Issue number1
DOIs
Publication statusPublished - Nov 1999
EventProceedings of the 1999 3rd International Conference on Nitride Semiconductors (ICNS'99) - Montpellier, France
Duration: 04 Jul 199909 Jul 1999

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