Electron paramagnetic resonance of the lattice damage in oxygen-implanted silicon

Publisher Website
Google Scholar
Abstract
The nature of the lattice damage produced at room temperature in ion‐implanted intrinsic and n‐type silicon has been studied as a function of 160‐keV O+ ion fluence using electron paramagnetic resonance(EPR). The known EPR spectra observed were the negative divacancy (Si‐G7), the neutral vacancy‐oxygen (Si‐S1), the neutral 4‐vacancy (Si‐P3), and the isotropic resonance at g = 2.0055 which is indicative of amorphous silicon. In addition, a new spectrum, labeled Si‐S2, was observed which may be the negative 4‐vacancy. Concentrations (number/cm2) for the various paramagneticdefects were determined as a function of ion fluence for fluences ranging from 1010 to 1017 O+/cm2. From these measurements we conclude that the lattice damage produced in crystalline silicon by individual ions whose maximum calculated energy density into atomic processes is ≲ 15 eV/Å ion consists of simple defects such as observed in electron‐ and neutron‐irradiated silicon. Furthermore, overlap effects in the lattice damage produced by ion implantation are small providing the maximum energy density into atomic processes is ≲ 1.5 × 1019 keV/cm3. For energy densities into atomic processes between ∼ 1.5 × 1019 and ∼ 1021 keV/cm3, there appears to be an accumulation of defect complexes which are characterized by a high concentration of defects whose electrons tend to be delocalized among the defects within the complex. Finally, our measurements indicate that ∼ 1021 keV/cm3 of energy into atomic processes must be accumulated in the form of lattice damage in order to convert crystalline silicon to the amorphous state.