Structure and electronic properties of trivacancy and trivacancy‐oxygen complexes in silicon

Abstract

We have recently found that the silicon trivacancy (V3) is a bistable defect that can occur in fourfold coordinated and (110) planar configurations for both the neutral and singly negative charge states [V. P. Markevich et al., Phys. Rev. B 80, 235207 (2009)]. Acceptor levels of V3 in both these configurations have been determined. It has also been shown that at T > 200 °C, the interaction of mobile trivacancies with interstitial oxygen atoms results in the formation of V3O complex with the first and second acceptor levels at Ec −0.46 and −0.34 eV. In the present work we identify donor levels arising from V3 and V3O complexes by means of deep level transient spectroscopy (DLTS) and high‐resolution Laplace DLTS on n+p silicon structures irradiated with 6 MeV electrons, combined with density functional modeling studies. It is found that both defects possess two donor levels in the (110) planar configurations. First donor levels at Ev +0.19 and +0.235 eV, and the second donor levels at Ev +0.105 and +0.12 eV are found for the V3 and V3O complexes, respectively.

Donor levels of the divacancy-oxygen defect in silicon

“…A comparison of the derived values for hole traps responsible for the dominant peaks with maxima at 120 K (E h ¼ 0.192 eV, a ¼ 7.4 Â 10 5 s À1 K À2 ) and 197 K (E h ¼ 0.360 eV, a ¼ 4.0 Â 10 6 s À1 K À2 ) in the spectrum with those known from the literature for radiation-induced defects in Cz-Si:B crystals allows us to associate these peaks with hole emission from the singly positive charge states of V 2 and the interstitial carbon-interstitial oxygen complex, respectively. 15,18,[24][25][26][27][28] It should be noted that the removal of the B i O i defect upon annealing at 200 C has not influenced significantly the concentration of V 2 .…”

“…1, resembles those reported in the literature for electron-irradiated boron-doped oxygen-rich Si crystals. 15,18,[24][25][26][27][28] We have determined electronic signatures {activation energy for hole (electron) emission [E h(e) ] and pre-exponential factor (a)} for the dominant traps from Arrhenius plots of T 2 -corrected hole emission rates measured with the use of LDLTS. A comparison of the derived values for hole traps responsible for the dominant peaks with maxima at 120 K (E h ¼ 0.192 eV, a ¼ 7.4 Â 10 5 s À1 K À2 ) and 197 K (E h ¼ 0.360 eV, a ¼ 4.0 Â 10 6 s À1 K À2 ) in the spectrum with those known from the literature for radiation-induced defects in Cz-Si:B crystals allows us to associate these peaks with hole emission from the singly positive charge states of V 2 and the interstitial carbon-interstitial oxygen complex, respectively.…”

“…15 We have argued in a recent work that in addition to the first donor level at E v þ 0.236 eV the V 2 O center possesses a second donor level at E v þ 0.087 eV. 18 The assignment of the above level to V 2 O has, however, been questioned recently. 19,20 Bearing in mind that the V 2 O center is a technologically important defect, which is thought to be responsible for the degradation of silicon based particle detectors, 21 we have carried out a detailed study of divacancy annealing in oxygen-rich p-type Si crystals and obtained conclusive information on electronic properties of the donor levels of the V 2 O defect.…”

In-growth of an electrically active defect in high-purity silicon after proton irradiation

“…Besides, the change of the di-vacancy concentration when the AU defect grows in is small compared to the change of the AU defect which suggests that the di-vacancy is not involved in the AU defect. Recent reports on the tri-vacancy in silicon 23,24 have shown that this defect is a bistable defect which has two donor levels in the lower half of the band gap at E V þ 0.106 eV and E V þ 0.193 eV, and that it becomes mobile at temperatures higher than 200 C. These observations exclude that the AU defect is related to the tri-vacancy. Thus, this discussion of vacancy defects points towards an AU defect which does not include vacancies.…”

DLTS Spectra of Silicon Diodes With P+—n–junction Irradiated With High Energy Krypton Ions

“…Авторы работы [17] предполагали, что указанные дефекты имеют вакансионную природу и основная их масса сконцентрирована в слое толщи-ной порядка 5 мкм на глубине среднего проективно-го пробега. В работе [18] показано, что тривакансия V 3 (−/0) имеет энергетический уровень E t = E c − 0,46 эВ, а комплекс «тривакансия -кислород» V 3 -O (−/0) -E t = E c − 0,455 эВ, что достаточно близко к получен-ным нами значениям. Таким образом, на настоящий момент наиболее вероятным представляется то, что наблюдаемый на спектрах DLTS пик Е4 обуслов-лен именно радиационными дефектами, возможно, многовакансионными комплексами, вероятность образования которых в конце пробега высокоэнерге-тических ионов достаточно велика [5,6].…”