Defect-state generation in Czochralski-grown (100) silicon rapidly annealed with incoherent light

Abstract

Defect-state generation in Czochralski-grown (100) silicon after rapid thermal annealing has been studied. Deep-level transient spectroscopy experiments have been carried out using Schottky barriers made on n- or p-type as-grown wafers after irradiation with a commercially available incoherent light annealing device. Neither electrical degradation nor electron-trap generation appeared in the case of n-type silicon wafers annealed for 5 s. On the other hand, the junction degradation together with the generation of three hole-trap levels H1(0.45 eV), H2(0.29 eV), and H3(0.3 eV) have been observed in boron-doped silicon using a short duration (5 s) plateau temperature between 850 and 1050 °C. Peak concentrations ranging from 1013 to 1014 cm−3 were measured after annealing at 1000 °C for the three hole traps. By increasing the plateau duration up to 20 s hole traps were no longer detected in boron-doped Czochralski-grown silicon. Moreover H2(0.29 eV) is stable at room temperature whereas both H1(0.45 eV) and H3(0.3 eV) decayed in unbiased samples after several weeks. A comparison of the trap properties with those of already known defect states suggested that residual 3D metal traces (Fe, V, Cr) might be responsible for all the observed defect states. In addition the intrinsic defects generated during the temperature plateau are likely to play a significant role in the final defect-state concentration after rapid thermal annealing.