Identification of vacancy–oxygen complexes in oxygen-implanted silicon probed with slow positrons

Defects and their annealing behavior for low (2×1015/cm2) and high (1.7×1018/cm2) doses of 180 keV oxygen-implanted silicon have been investigated by the coincidence Doppler broadening (CDB) and lifetime measurements in variable-energy positron annihilation spectroscopy. In the low-dose sample, diva...

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Veröffentlicht in:Journal of applied physics 2004-04, Vol.95 (7), p.3404-3410
Hauptverfasser: Fujinami, M., Miyagoe, T., Sawada, T., Suzuki, R., Ohdaira, T., Akahane, T.
Format: Artikel
Sprache:eng
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Zusammenfassung:Defects and their annealing behavior for low (2×1015/cm2) and high (1.7×1018/cm2) doses of 180 keV oxygen-implanted silicon have been investigated by the coincidence Doppler broadening (CDB) and lifetime measurements in variable-energy positron annihilation spectroscopy. In the low-dose sample, divacancies are induced throughout the entire implantation region. In the vacancy-oxygen coexisting region (300–500 nm depths), by raising the annealing temperature to 600 °C, vacancy–oxygen VxOy complexes with one vacant site are formed and, simultaneously, the migration of oxygen begins to takes place. In the vacancy-rich region (−200 nm depths), the evolution of simple vacancy clusters to V4 is mainly observed below 600 °C. From CDB and lifetime measurements, it has been proven that after annealing at 800 °C, the VxOy complexes are formed throughout the implanted region and they contain four vacant sites and a high ratio of y to x. On the other hand, high-dose implantation at 550 °C produces the VxOy complexes with a lifetime of a 430 ps in the near-surface region (less than 200 nm deep) and annealing at 1100 °C leads to the highest ratio of y to x. These complexes cannot be annealed out even by annealing at 1350 °C, and their structure is found to be very similar to that for the electron-irradiated amorphous SiO2.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.1652241