Mecanismes de recuit des bilacunes produites dans le silicium par irradiation de protons
Abstract
The subject of the present thesis is the study of divacancy annealing in 8 MeV proton irradiated silicon. Using data from infrared absorption, positron annihilation, scanning differential calorimetry, and electron paramagnetic resonance, divacancy annealing behaviour was studied from room temperature up to complete divacancy disappearance from the samples. The comparison between infrared and positron annihilation data enabled the identification of the partial divacancy annealing below 200°C, with the diffusion of interstitials released from clusters created during irradiation. Above 200°C, a second annealing stage was determined to coincide with the onset of divacancy mobility and association into a new defect, having a similar electronic density as the divacancy. Positron lifetime measurements showed that these vacancy-type defects coalesce into larger open volume defects (tetravacancies, hexavacancies) only above 450°C. In addition, using all the available data, we attempted to identify the different heat release sources, measured with calorimetry, during annealing. We show that approximately 5% of the defects created during irradiation at 77K are found in the samples at room temperature before subsequent annealing. Furthermore, the data allow us to assert that divacancy annealing is responsible for at most 50% of the measured energy. The remainder likely arises from processes involving interstitials, present in the samples as a variety of clusters of diverse sizes, produced in the highly damaged regions resulting from collision cascades of recoiling atoms with energies above 10 keV during irradiation.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 2005
- Bibcode:
- 2005PhDT.......188P