Modelling spatial distribution of defects and estimation of electrical degradation of silicon detectors in radiation fields at high luminosity

Abstract

The irradiation represents a useful tool for determining the characteristics of defects in semiconductors as well as a method to evaluate their degradation, a fact with important technological consequences. In this contribution, starting from available data on the degradation of silicon detector characteristics in radiation fields, these effects are explained in the frame of a model that supposes also the production of the Si FFCD defect due to irradiation. The displacement threshold energies different for different crystallographic axes, considered as parameters of the model, are established and the results obtained could contribute to clarify these controversial aspects. Predictions of the degradation of electrical parameters (leakage current, effective carrier concentration and effective trapping probabilities for electrons and holes) of DOFZ silicon detectors in the hadron background of the LHC accelerator, supposing operation at −10 °C, are done. The non-uniformity of the rate of production of primary defects and of complexes, as a function of depth, for incident particles with low kinetic energy was obtained by simulations using some particular and very simplifying assumptions, suggesting the possible important contribution of the low-energy component of the background spectra to detector degradation.