Spectroscopy of neutron irradiation induced deep levels in silicon by microwave probed photoconductivity transients

A contactless technique for simultaneous measurements of the carrier lifetime and the parameters of deep levels has been applied. This method is based on microwave probed pulsed photoconductivity (MW-PC) spectroscopy in the wavelength range between 0.5 and 4 μm. Several deep levels in the range of 0.2–0.6 eV have been resolved from spectral analysis of microwave probed photoconductivity amplitude variations in the samples of Si grown by magnetic field applied Czochralski (MCz) technology. An amplitude of the revealed MW-PC spectral steps showed an increase with neutron irradiation fluence indicating an enhancement of density of the specific defects. Simultaneous variations of recombination lifetime with fluence of the reactor neutrons from 1012 to 3×1016 n/cm2 in the MCz Si samples have been examined. Recombination features of the irradiated and annealed MCz Si structures are discussed by comparing carrier recombination parameters and deep-level MW-PC spectral data with characteristics measured by deep-level-transient spectroscopy (DLTS) in the range of moderate irradiation fluences.