ION-SOLID CHEMISTRY IN IMPLANTED AMORPHOUS SIO2

It is demonstrated that types and concentrations of predominant defects produced during implantation in amorphous SiO2 are determined by the nature and strength of the chemical interaction of implanted ions with substrate structure. Implants can be classified into three types, I, II, and III, from a view of ion-solid chemistry. Implants (M) belonging to type I extract oxygen atoms from the silica network to form M-O bonds, leaving Si-Si bonds at concentrations comparable to implant bonds, while implants (A) belonging to type II replace oxygen atoms in the network to form Si-A bonds, producing O2 molecules and peroxy radicals as dominant defects. Boron and fluorine are typical implants of types I and II, respectively. Implants with a weak chemical reactivity with the substrate structures belong to type III and a major fraction of this type of implants occur as homomolecules or colloids of implanted ions. Nitrogen and copper are-examples of type III.