Abstract
Forming a good Ge/dielectric interface is important to improve the electron mobility of a Ge metal oxide semiconductor field-effect transistor. A thin yttrium germanate capping layer can improve the properties of the Ge/GeO 2 system. We employ electronic structure calculations to investigate the effect of oxygen vacancies in yttrium-doped GeO 2 and the yttrium germanates Y 2Ge 2O 7 and Y 2GeO 5. The calculated densities of states indicate that dangling bonds from oxygen vacancies introduce in-gap states, but the system remains insulating. However, yttrium-doped GeO 2 becomes metallic under oxygen deficiency. Y-doped GeO 2, Y 2Ge 2O 7 and Y 2GeO 5 are calculated to be oxygen substoichiometric under low Fermi energy conditions. The use of yttrium germanates is proposed as a way to effectively passivate the Ge/dielectric interface. This journal is © 2012 the Owner Societies.
Original language | English (US) |
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Pages (from-to) | 14630 |
Journal | Physical Chemistry Chemical Physics |
Volume | 14 |
Issue number | 42 |
DOIs | |
State | Published - 2012 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: AC and AD acknowledge financial support from the EU FP7-PEOPLE-2010-IEF project REACT-273631.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry