Anomalously low ionization energy of phosphorus atoms in the electric field of silicon p-n junctions in the temperature range 10-20 K

Abstract

Abstract The work extends the study of the ionization properties of phosphorus atoms as trapping/emission centres in the electric field of silicon p-n junctions operating at low temperatures. The goal is describing the ionization of phosphorus atoms by a single effective parameter, the ionization energy of phosphorus energy levels Eion . An approach to the study is based on manipulating the space charge concentration Neff in a nonirradiated silicon p+/n/n+ structure via filling phosphorus donors with electrons supplied by a laser pulse. Extracting the Neff from the experimental current pulse response shapes recorded at variable temperature and pulse repetition rate allowed building Arrhenius plot for evaluating Eion in the electric field. This value is shown to be 6.4±1.1 meV that is paradoxically low, being about 7 times less than the referred data.