Defect levels of proton-irradiated silicon with doses ranging from 1 × 1012 cm−2 to 1 × 1013 cm−2

Abstract Schottky diodes of n-type silicon have been irradiated by 800 keV and 1 MeV protons at doses ranging from 1 × 10 12 cm −2 to 1 × 10 13 cm −2 . Thermally Stimulated Capacitance (TSCAP), capacitance-voltage (CV) and Deep Level Transient Spectroscopy (DLTS) have been applied for sample analysis. By TSCAP measurements a strong compensation effect has been observed for irradiation doses up to 5 × 10 12 cm −2 . At least five deep levels have been observed in the DLTS spectra, but the E(200) trap, located at E c − 0.36 eV, was only revealed by the fitting procedure. An additional new pure damage level, labelled E(110), with an energy of E c − 0.19 eV and a capture cross section of about 5 × 10 −16 cm 2 has been also observed in the highly damaged region. The variations of the DLTS signal with pulse amplitude of the E c − 0.3 eV level, called E(170), has been found to be different of what is obtained at low dose irradiations: a dip followed by a peak in concentration near the maximum of implanted ions is suggested. A possible explanation of such behavior is discussed. We also report the possibility of an overdoping effect near the proton distribution before thermal annealing.