DLTS spectra of silicon diodes with p+-n-junction irradiated with high energy krypton ions

Abstract

p+-n-Diodes have been studied. The diodes were manufactured on wafers (thickness 460μm, (111) plane) of uniformly phosphorus doped float-zone-grown single-crystal silicon. The resistivity of silicon was 90Ωcm and the phosphorus concentration was 5×1013cm−3. The diodes were irradiated with 250MeV krypton ions. The irradiation fluence was 108cm−2. Deep-level transient spectroscopy (DLTS) was used to examine the defects induced by high energy krypton ion implantation. The DLTS spectra were recorded at a frequency of 1MHz in the 78–290K temperature range. The capacity-voltage characteristics have been measured at a reverse bias voltage from 0 to −19 V at a frequency of 1MHz. We show that the main irradiation-induced defects are A-centers and divacancies. The behavior of DLTS spectra in the 150–260K temperature range depends essentially on the emission voltage Ue. The variation of Ue allows us to separate the contributions of different defects into the DLTS spectrum in the 150–260K temperature range. We show that, in addition to A-centers and divacancies, irradiation produces multivacancy complexes with the energy level Et = Ec−(0.5±0.02) eV and an electron capture cross section of ~4×10–13cm2.