EPITAXIAL REGROWTH OF C-IMPLANTED AND N-IMPLANTED SILICON AND ALPHA-QUARTZ

We have investigated the epitaxial regrowth and diffusion during therm al annealing of C- and N-implanted Si and alpha-quartz, utilising Ruth erford Backscattering Spectroscopy in Channeling geometry (RBS-C) and nuclear reaction analysis (NRA). In both materials solid phase epitaxi al regrowth was observed to occur at temperatures around 550 degrees C (Si) and 1000 degrees C (SiO2). Epitaxial regrowth in Si was found to be strongly retarded compared to self-ion-implantation and the epitax ial recrystallisation front stopped at about the depth of maximum impl ant concentration even after annealing at 900 degrees C. In fact, the implanted N-concentration profile in Si was found to be unchanged up t o this temperature, This points at a chemical reaction between Si and the implanted C- and N-atoms, which obviously suppresses epitaxial rec rystallisation. In SiO2 almost no nitrogen could be detected in the N- implanted sample at T greater than or equal to 900 degrees C, i.e. no significant amount of impurity atoms was present during recrystallisat ion, which may hinder or suppress the regrowth process. A similar beha vior is expected for the implanted C-atoms. In fact, epitaxial recryst allisation in the C-implanted alpha-quartz sample was found to be almo st complete, except for a small amount of defects in the recrystallise d matrix. (C) 1998 Elsevier Science B.V.