CHARACTERIZATION OF DEEP LEVELS INTRODUCED BY ALPHA-RADIATION IN N-TYPE SILICON

A detailed deep-level transient spectroscopy study of the characterist ics of deep-level defects introduced by 5.48 MeV alpha particles in lo w-doped n-Si is reported. The deep-level characteristics studied inclu de emission rate signatures, activation energies, capture cross sectio ns and their temperature dependence, and defect concentrations and the ir spatial profiles. At least five deep levels in the upper-half band gap and two levels in the lower-half gap have been observed as a resul t of irradiation and characterized in detail. A systematic study of th eir generation rates up to a dose of about 3 X 10(10) alpha particles/ cm2 has been performed providing insights into the dose dependence of their formation mechanisms. Interesting room temperature transformatio n phenomena have been observed in our deep-level spectra during room t emperature storage of the irradiated samples. Extensive isochronal the rmal annealing measurements have been carried out to obtain data on th e anneal-out characteristics of the radiation-induced deep levels and to identify these with the known defects wherever possible. A number o f new annealed-in levels have been observed during this investigation. A detailed comparison with the published results is presented.