Point defect production efficiency in ion irradiated 4H-SiC

The defects introduced in 4H-SiC by irradiation with different ions are investigated by deep level transient spectroscopy measurements in the temperature range 100-700 K. The defects were generated with 60 MeV H+ and with 6.7 MeV C+ in the fluence range 3.5 x 10(11)-1.5 x 10(12) cm(-2) and 10(9)-10(10) cm(-2), respectively. The ion beam cross the entire epitaxial layer and introduce an almost uniform defect concentration. Deep level transient spectroscopy measurements show the formation of three main traps located E-c - 0.68 eV and E-c - 0.98 eV and E-c - 1.5 eV independently on the irradiating ion. The trap concentration increases linearly with ion fluence suggesting that these traps are associated to the point defects generated by ion irradiation. Surprisingly the determined values of defect production efficiency (defects/eV) depend on the type of ion and they decreases by increasing the elastic energy loss for all the introduced defects. This behaviour can be related to the local point defect (vacancies and self interstitials) recombination which is higher in the denser cascade.\