Solid-Phase-Epitaxial Growth in Ion-Implanted Silicon

Abstract

The details of solid-phase-epitaxial (SPE) growth are obtained in ion-implanted silicon amorphous layers after furnace annealing in the temperature range 450 to 600°C. The kinetics of amorphous-crystalline interfaces and the nature of residual damage in SPE grown layers are studied by high-resolution, cross-section electron microscopy. The number density of dislocation loops in the dislocation bands below the amorphous layers in as-implanted specimens are found to decrease with decreasing substrate temperature and increasing mass of the incident ions. Substitutional concentrations of solutes in “defect-free” SPE grown layers are found to exceed retrograde solubility limits as much as a factor of 560 in Si–Bi system. Depending upon implantation conditions, the observed substitutional concentrations of antimony in silicon vary from (1.3 to 2.5) × 1021 cm−3 compared to retrograde solubility limit of 7.0 × 1019 cm−3. These observations are found to be in good agreement with the theoretical estimates of maximum concentrations. The solute concentrations in the excess of solubility limits can be precipitated out by heat treatments at relatively higher temperatures.