Carbon-hydrogen related defects in SiGe observed after dc H plasma treatment

In the present study, the electrical and structural properties of two carbon-hydrogen related DLTS levels (E42 and E262) that appear after hydrogen plasma treatment are investigated in diluted Si1−xGex alloys. E42 and E262 were previously observed in pure Si after hydrogenation by a dc hydrogen plasma. They were correlated with different charge states of a carbon-hydrogen complex, where H is located on the anti-bonding position at the carbon atom (CH1AB). By utilizing the Laplace DLTS technique we show that the DLTS peaks E42 and E262 consist of several components in Si1−xGex. These components can be quantitatively explained by the presence of Ge atoms in the first and second nearest-neighborhood of the CH1AB complex. The observed Laplace DLTS spectra indicate a preference of hydrogen to bond to carbon with a Ge atom in its first nearest-neighborhood.