Photoluminescence of Radiation Defects in Ion-Implanted 6H SiC
Radiation defects were introduced into 6H SiC by ion implantation and by electron bombardment. The defects produce a new low-temperature luminescence that is independent of the implanted ion, and one portion, the D1 spectrum, persists after a 1700°C anneal. A comparison of the D1 spectrum in ion- and electron-bombarded samples shows that its intensity is strongly dependent on defect concentration, suggesting that the luminescence center is a pure-defect complex, possibly a divacancy. The D1 spectrum, which was previously observed in cubic SiC, has a strong vibronic structure with localized and resonant modes. In 6H SiC it is repeated three times, due to the three inequivalent sites in this polytype. D1 has an unusual temperature dependence, the low-temperature (1.4°K) spectrum being extinguished as the high-temperature (77°K) form is activated. The abrupt change of spectrum is attributed to a lattice distortion at the low temperature. The changes in luminescence on annealing are correlated with changes in electrical properties observed in ion-implanted samples by Marsh and Dunlap.
Physical Review B
- Pub Date:
- April 1972