EMRS 2010 Spring Meeting on Post-Si-CMOS Electronic Devices - The Role of Ge and III-V Materials Strasbourg, FRANCE, JUN 07-11, 2010
The identification of a nontrigonal Ge dangling bond at SiO2/Si1-xGex/SiO2 heterostructures and its electrical activity are discussed, both from experimental and theoretical points of view. This dangling bond is observed from multifrequency electron-spin resonance experiments performed at 4.2 K, for typical Ge concentrations in the range 0.4 <= x >= 0.85. The electrical activity of this defect is revealed from capacitance-voltage characteristics measured at 300 and 77 K, and is found to behave like an acceptor defect. First-principles calculations of the electronic properties of this Ge dangling bond indicate that its energy level approaches the valence band edge of the Si1-xGex layer as the Ge content increases, confirming its acceptor-like nature. (C) 2010 Elsevier B.V. All rights reserved.