EPR and RBS study of defects produced by MeV ion implantation into silicon

Electron paramagnetic resonance and Rutherford backscattering have been used to investigate the damage produced by implanting (100) silicon wafers with either 3 MeV Au+ or 2 MeV Si+ ions at liquid nitrogen temperature, 300 or 500 K (Au only). For samples implanted at liquid nitrogen temperature the EPR spectra include those of the neutral 4-vacancy (Si-P3), the silicon di-interstitial (Si-P6), the D centre (indicative of amorphous silicon) and a broad anisotropic resonance; their concentration in these samples is determined as a function of dose in the range 1013-1015 Si+ cm-2 and 1012-1014 Au+ cm-2. The EPR spectrum for any dose of Au+ ions at the low implantation temperature is very similar to the equivalent spectrum for an approximately 20 times larger dose of Si+ ions. At the lowest doses there is no measurable D centre concentration. For implants at 300 K of 5x1013-5x1015 Au+ cm-2 and of 3x1015 Si+ cm-2 an amorphous layer is produced and the EPR spectrum reveals only D centres. However, no such layer is present and point defects are revealed by EPR for an implant of 5x1014 Si+ cm-2 at 300 K or 5x1014-5x1015 Au+ cm-2 at 500 K. (orig.)