Divacancy profiles in MeV helium irradiated silicon from reverse I-V measurement

The application of high-voltage reverse current to voltage characteristics for characterization of ultra-deep radiation defect profiles in ion irradia ted silicon p-i-n diodes is presented. Theoretical analysis shows that moni toring of the reverse current gradient with increasing bias can give, in co mbination with Deer Level Transient Spectroscopy (DLTS) and Capacitance-Vol tage (C-V) measurement, quantitative information about the distribution of generation defect centres with the highest emissivity. The method is subseq uently used for characterization of deep-level profiles in p(+)pnn(+) power diodes irradiated by He2+ ions with energies 11-22 MeV and fluences 2.5 x 10(9)-1.2 x 10(10) cm(-2). The results show that the method can non-destruc tively determine the concentration profile of divacancies, the dominant gen eration centre in helium irradiated silicon, in the depths of the device wh ere application of other methods usually fails. (C) 1999 Elsevier Science B .V. All rights reserved.