Point defects observed in crystalline silicon implanted by MeV Si ions at elevated temperatures

Abstract

Si(100) samples of n-type have been implanted with 5.6 MeV 28Si 3+ ions at elevated temperatures up to 400°C using doses of 10 7 to 10 9 cm −2. Deep level transient spectroscopy was utilized for sample analysis, and after implantation at 400°C, three new levels occur ∼0.22, ∼0.34 and ∼0.47 eV below the conduction band edge ( E c). Evidence is obtained for a high-order vacancy complex causing the E c − 0.22 and E c − 0.47 eV levels, which emerge above 300°C through a gradual shift of the divacancy peaks at E c − 0.23 and E c − 0.43 eV, respectively. The E c − 0.34 eV level is most likely due to a complex involving impurities with concentration less than 10 14 cm −3 in the silicon lattice. Furthermore, the vacancy-oxygen level at E c − 0.18 eV increases in amplitude with temperature and is the dominating peak at 400°C.