Transformation of electrically active defects as a result of annealing of silicon implanted with high-energy ions

Abstract

Deep-level transient spectroscopy is used to study both the concentration profiles of defects introduced into silicon during the implantation of 14-MeV boron ions and the transformation of these defects as a result of subsequent annealing at temperatures in the range from 200 to 800°C. It is ascertained that implantation gives rise to a standard set of vacancy-containing radiation defects (the oxygen-vacancy and phosphorusvacancy complexes and divacancies) and to a center with the level located at E _c − 0.57 eV. Heat treatments at temperatures of 200–300°C bring about the disappearance of all vacancy-containing complexes at a distance from the surface h > 12−9 µm. Most likely, this phenomenon is caused by the decomposition of interstitial-containing complexes located at a depth h > 12−9 µm and their annihilation with the vacancy-containing complexes. Heat treatments at higher temperatures bring about both a further narrowing of the layer that still contains the vacancy-type defects to h ≈ 6 µm at 500°C and a change in the set of observable electrically active centers in the temperature range from 400 to 500°C. Specific features of the annealing of radiation defects after high-energy ion implantation are caused by spatial separation of the vacancy-and interstitial-containing defects.