262 Crystal Growth and Evaluation of Silicon for VLSI and ULSI
and an acceptor level 0.54 eV below the conduction band. Both of these levels are believed to
be due to substitutionally occupied gold atoms in the silicon lattice sites [79]. Gold is a double-
level impurity in silicon, introducing both an acceptor level and a donor level in the bandgap
between the conduction band and the valence bands [80]. The impurity center can change
charge states in the semiconductor only by the emission of carriers, either to the conduction
band or to the valence band, and the capture of carriers from one of the bands. Gold is also
introduced into the silicon bulk for specic applications such as IR detection applications.
It has been shown that gold was get ...