Affiliation
Univ Arizona, Dept Chem & BiochemUniv Arizona, Dept Chem & Environm Engn
Issue Date
2017-05
Metadata
Show full item recordPublisher
A V S AMER INST PHYSICSCitation
Reaction of aqueous ammonium sulfide on SiGe 25% 2017, 35 (3):03E110 Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and FilmsRights
© 2017 American Vacuum Society.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
SiGe 25% substrates were treated with aqueous solutions of ammonium sulfide with and without added acid to understand the adsorption of sulfur on the surface. X-ray photoelectron spectroscopy showed no sulfide layer was deposited from aqueous (NH4)(2)S alone and instead both Si and Ge oxides formed during immersion in the sulfur solution. The addition of hydrofluoric and hydrochloric acids dropped the pH from 10 to 8 and deposited sulfides, yet increased the oxide coverage on the surface and preferentially formed Ge oxides. The sulfur coverage grew with increasing concentrations of acid in the aqueous (NH4)(2)S. The simultaneous deposition of O and S is suspected to be the result of oxidized sulfur species in solution. Metal-insulator-semiconductor capacitor (MISCAP) devices were fabricated to test the electrical consequences of aqueous ammonium sulfide wet chemistries on SiGe. MISCAPs treated with acidic ammonium sulfide solutions contained fewer interface defects in the valence band region. The defect density (D-it) was on the order of 10(+12) cm(-2) eV(-1). The flat band voltage shift was lower after the acidic ammonium sulfide treatment, despite the presence of surface oxides. Adsorption of S and potentially O improved the stability of the surface and made it less electrically active. (C) 2017 American Vacuum Society.Note
12 month embargo; published online: 27 April 2017ISSN
0734-21011520-8559
Version
Final published versionSponsors
Lam Research CorporationAdditional Links
http://avs.scitation.org/doi/10.1116/1.4982223ae974a485f413a2113503eed53cd6c53
10.1116/1.4982223