Hydrogen self-trapping near silicon atoms in Ge-rich SiGe alloys

Infrared absorption spectroscopy and ab initio density functional modeling are used to investigate hydrogen defects that are stable at and above room temperature in proton-implanted Ge-rich SiGe alloys. We find that Si atoms are effective nucleation sites for hydrogen, leading to the formation of a dominant defect closely related to the H-2(*) dimer in pure Si and Ge. The minority Si species in the alloys stabilizes the new complex, and strongly reduces the trapping efficiency of hydrogen by vacancies and self-interstitials. (c) 2006 American Institute of Physics.