Effect of Nitrogen-Doping on the Properties of Radiation Defect Centers in FZ Silicon

Abstract

High-resolution photoinduced transient spectroscopy (HRPITS) has been applied to determining the properties and concentrations of radiation defect centers formed in FZ silicon single crystals subjected to doping with phosphorus in neutron transmutation processes. The studies were performed immediately after the neutron irradiation on the samples with the resistivity of the order of 105 Ωcm. The preset target resistivity was around 2000 Ωcm. The N-doping effect on the material radiation damage has been demonstrated. It is shown that in the N-enriched material, the radiation defect centers with activation energies of 81, 125, 160, 185, and 390 meV are not observed and the concentrations of the defect centers with activation energies of 46, 84, 133, 140, 265, 300, 380, 460, and 546 meV are significantly lower than those in the N-free material. We also show that the majority of defect centers produced by the irradiation of FZ silicon with fast neutrons are also observed after neutron transmutation doping.

Investigation of nitrogen enriched silicon for particle detectors

“…For DOFZ this result is expected, as measurements done in [1] show that no improvements were observed for oxygenated silicon under irradiation with neutrons. For NIT the predicted improvements from measurements done in [3] could not be confirmed. The most likely cause being the lower concentration of the di-interstitial nitrogen defect.…”

“…However the di-interstitial nitrogen defect is only stable up to 900 • C and thus the high temperature processing is the most likely cause for the nitrogen loss [8,9]. The thermal budget to which the wafers were exposed during device processing was dominated by the initial oxidation steps at 1100 • C, with a total estimated time of about 4 h. Thus possible improvements from nitrogen enrichment will be smaller than shown in [3]. The following measurements will aim to understand, if any advantages from nitrogen enrichment are retained.…”

“…A new candidate to enhance the performance of silicon in radiation environments is nitrogen [3]. The idea is that nitrogen interacts with vacancies during crystal growth and high temperature steps during detector fabrication.…”