Trivacancy and trivacancy-oxygen complexes in silicon: Experiments andab initiomodeling

Abstract

A center from the family of "fourfold coordinated ͑FFC͒ defects", previously predicted theoretically, has been experimentally identified in crystalline silicon. It is shown that the trivacancy ͑V 3 ͒ in Si is a bistable center in the neutral charge state, with a FFC configuration lower in energy than the ͑110͒ planar one. V 3 in the planar configuration gives rise to two acceptor levels at 0.36 and 0.46 eV below the conduction band edge ͑E c ͒ in the gap, while in the FFC configuration it has trigonal symmetry and an acceptor level at E c − 0.075 eV. From annealing experiments in oxygen-rich samples, we also conclude that O atoms are efficient traps for mobile V 3 centers. Their interaction results in the formation of V 3 O complexes with the first and second acceptor levels at E c − 0.46 eV and E c − 0.34 eV. The overall picture, including structural details, relative stability, and electrical levels, is accompanied and supported by ab initio modeling studies.

Characterization of Radiation Defect Centers in Neutron Irradiated Si Using Inverse Laplace Transformation to Analysis of Photocurrent Relaxation Waveforms

“…The identication was done on the grounds of the results presented in Refs. [1,17,19,20]. These results show that V 3 in the form of chain built up of single vacancies occurring in (110) plane gives rise to two acceptor levels located at a small distance above the midgap [1,17,19].…”

“…These results show that V 3 in the form of chain built up of single vacancies occurring in (110) plane gives rise to two acceptor levels located at a small distance above the midgap [1,17,19]. According to DLTS measurements, the two levels corresponding to V 3 (2-/-) and V 3 (-/0) are located at 0.36 and 0.46 eV below the conduction band edge (E c ), respectively [17]. Moreover, the results of ab initio calculation indicate that the rst acceptor level of V 3 with the C 2v symmetry is placed deeper in the bandgap at E c − 0.50 eV [1,17,19].…”

“…According to DLTS measurements, the two levels corresponding to V 3 (2-/-) and V 3 (-/0) are located at 0.36 and 0.46 eV below the conduction band edge (E c ), respectively [17]. Moreover, the results of ab initio calculation indicate that the rst acceptor level of V 3 with the C 2v symmetry is placed deeper in the bandgap at E c − 0.50 eV [1,17,19].…”

“…[1,17,19,20]. These results show that V 3 in the form of chain built up of single vacancies occurring in (110) plane gives rise to two acceptor levels located at a small distance above the midgap [1,17,19]. According to DLTS measurements, the two levels corresponding to V 3 (2-/-) and V 3 (-/0) are located at 0.36 and 0.46 eV below the conduction band edge (E c ), respectively [17].…”

“…[16,17], the traps TR5 and TR8, detected in the both kinds of samples, are attributed to the divacancyoxygen complex in various charge states: V 2 O (2-/-) and V 2 O (-/0), respectively. The formation of this complex is through the interaction of migrating divacancy with interstitial oxygen [16].…”