Peer-Reviewed Journal Details
Mandatory Fields
Maffeis, TGG and Clark, SA and Dunstan, PR and Wilks, SP and Evans, DA and Peiro, F and Riechert, H and Parbrook, PJ;
1999
November
GaN cleaning by Ga deposition, reduction and re-evaporation: An SXPS study
Validated
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Optional Fields
176
1
751
754
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 Delta E-k=+ 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 Delta E-k=- 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.
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