Abstract
Radiation-induced divacancy-related levels in high-purity oxygen-enriched n-type silicon have been studied with the use of deep level transient spectroscopy (DLTS) and Laplace-DLTS. It has been shown that heat treatment at 250degreesC results in a shift of the divacancy (V-2)-related peaks observed by 'standard' DLTS. Using Laplace-DLTS it is demonstrated that the shift is due to annealing of V-2 and formation of a new acceptor centre. The new centre has presumably two negative charge states: singly and doubly negative. The formation of the new centre holds a close one-to-one correlation with the annealing of V-2, indicating that the new centre is a result of divacancy interaction with an impurity or a defect. The close position of the electronic levels of the new centre to that of V-2 suggests a similar electronic and microscopic structure of the new centre to V-2, and a tentative identification is a divacancy-oxygen centre.
