Observation of the formation of electron irradiation induced secondary defects in Czochralski silicon

Electron irradiation and in situ observation of Czochralski silicon are carried out in a 2 MeV ultra-high voltage electron microscope at temperatures from room temperature to 400° C. Two kinds of irradiation-induced interstitial type secondary defects are found to be formed; (1) dislocation loops formed in the bulk of the specimen and (2) dislocation loops formed near the electron incident surface of the specimen. The experimental results show that supersaturation of interstitials occurs in the region near the electron incident surface of the specimen during irradiation. It is suggested that some vacancy clusters are formed by irradiation with a high electron flux.