Gold–hydrogen complexes in silicon

Electron emission from gold and gold–hydrogen complexes in n-type silicon have been studied using high resolution (Laplace) DLTS. This technique permits a clear separation of defects which have very similar carrier emission characteristics. At low hydrogen concentrations our results confirm those inferred previously from conventional DLTS. However by using ‘Laplace’ DLTS it has been possible to study the gold acceptor and G4 defect independently. G4 has an activation energy of 542±8 meV. By directly measuring the electron capture cross-section of G4 we conclude that it is acceptor like. At high hydrogen concentrations additional complexes are formed, notably a defect with emission characteristics similar to G4 (referred to as G4′) with an activation energy of 578±10 meV, and a state with an activation energy for electron emission of 276 5 meV. We put forward the hypothesis that these may be charge states of AuH2 or AuH3 complexes.