The Role of Si Self-interstitial Atoms in the Formation of Electrically Active Defects in Reverse-Biased Silicon n~+–p Diodes upon Irradiation with Alpha Particles

摘要

Results of a study of changes in electrical characteristics of n~+–p diodes onboron-doped epi-silicon induced by irradiation with alpha particles under appliedreverse bias voltages are presented. It is found that the irradiation results in asignificantly lower introduction rate of carrier-compensating radiation-induceddefects (RIDs) in the space charge region of the reverse-biased structurescompared with those in the neutral base region and in similar diodes irradiatedwithout bias. The dominant hole and electron emission signals in the capacitancetransient spectra of the irradiated diodes are characterized and identified withenergy levels of some known RIDs in moderately doped p-type Si:B. Changes inconcentration of the defects are monitored after postirradiation minority carrierinjection and thermal treatments. It is argued that the observed effect of thereduced concentration of RIDs in the space charge regions of the diodes is relatedmainly to some specific features of the silicon self-interstitials (I_(Si)): a very strongdependence of their thermal stability on the charge state and a highly enhancedmobility in p-type Si under minority carrier injection conditions. The activationenergy of electron emission from the doubly positively charged state of I_(Si) isdetermined.