Strain development and damage accumulation during neon ion implantation into silicon at elevated temperatures

Abstract

The development of mechanical strain and accumulation of damage in silicon single crystals implanted with Ne ions to doses in the range of 0.1–1.0 x1017 cm-² at temperatures from 200 to 600 °C were investigated employing Rutherford backscattering spectrometry, high resolution x-ray diffraction ~HRXRD! analysis and cross section transmission electron microscopy (XTEM). Two distinct layers have been found in the implanted material: A near-surface layer (<0.2 μm thick) where no extended defects are observed and a buried layer (≈0.5 μm thick) containing a dense array of dislocation loops and defect clusters. XTEM analysis revealed a distribution of small spherical cavities presumably filled with Ne, with a diameter <4 nm, extending along the entire depth of the implanted layer. HRXRD studies showed the presence of a positive strain (of expansion), irrespective of the implanted dose and temperature. The findings are discussed in terms of the proposed model which assumes that vacancy-type defects are consumed during the formation of Ne bubbles.