SILICON BASED MATERIALS FOR APPLICATION IN SPINTRONICS

Abstract

The effect of enhanced hydrostatic pressure (HP, up to 1.1 GPa) applied at up to 1270 K (HT) on Si:V, Si:Cr, Si:V,Cr and Si:Mn prepared by implantation of respective metallic ions (doses 1x1015 — 1x1016 cm-2, at energy 160 keV or 200 keV) into (001) oriented Czochralski grown Si, has been investigated by Secondary Ion Mass Spectrometry, magnetometry and X-Ray methods. Implantation produces amorphous silicon (a-Si) near the implanted ions range. Quasi — epitaxial re — growth of a-Si takes place at HT. The V, Cr and Mn concentration profiles do not depend markedly on HP if applied below 1000 K. Marked diffusion of implanted atoms toward the sample surface is observed in the case of processing at > 1000 K under 105 Pa, especially in the case of Si:Cr and Si:Mn. Under HP this diffusion is even more pronounced, re-crystallization of a-Si is retarded and the a-Si / Si interface becomes enriched with metallic atoms. Processing of Si:V, Si:Cr and Si:Mn at ≤ 723 K results in distinct ferromagnetic ordering, detectable also above 50 K. This means that the new Si-V, Si-Cr and Si-Mn materials belonging to the family of Diluted Magnetic Semiconductors may be produced.