Annealing of the divacancy-oxygen and vacancy-oxygen complexes in silicon

• DOI: 10.1103/physrevb.75.155202
• Publication Date: 2007-04-09T23:09:35Z
• Authors: M. Mikelsen; J. H. Bleka; J. S. Christensen; E. V. Monakhov; B. G. Svensson; J. Härkönen; B. S. Avset
• Keywords: 0103 physical sciences; 01 natural sciences

After low dose electron irradiation, annealing kinetics of divacancy-oxygen (V{sub 2}O) and vacancy-oxygen (VO) complexes in carbon-lean n-type magnetic Czochralski (MCZ) and diffusion-oxygenated float-zone (DOFZ) Si samples has been studied in detail. The samples were of n type with a phosphorus doping concentration in the 10{sup 12} cm{sup -3} range, and the analysis was conducted by means of deep-level transient spectroscopy (DLTS). An exponential decrease in the V{sub 2}O concentration with time during isothermal annealing at temperatures in the range 275-355 deg. C has been observed. The activation energy for the V{sub 2}O annealing is found to be 2.02{+-}0.12 eV, with a preexponential factor in the 10{sup 13} s{sup -1} range, which strongly suggests that dissociation of V{sub 2}O is the dominating mechanism. The binding energy of the vacancy to the V{sub 2}O complex has been estimated as {approx}1.7 eV. An increase in the VO concentration is observed in the initial phase of the V{sub 2}O annealing, which is supportive of V{sub 2}O dissociation through the reaction V{sub 2}O{yields}VO+V. After the initial increase, a close to first order decrease in the VO concentration is observed, consistent with that VO mainly anneals by migration and trapping at oxygen interstitial sites, similarlymore » to what has been reported in previous high-dose studies using infrared spectroscopy. The vacancy-oxygen-hydrogen complex (VOH) is formed after long time annealing. The formation of VOH is followed by a decrease at the same rate as VO, and it is suggested that VOH dissociates (VOH{yields}VO+H). The experimental data have been compared with kinetic simulations and show good agreement with a model where the main processes are dissociation of VO and V{sub 2}O, migration and subsequent trapping of VO ultimately giving rise to the electrically inactive vacancy-dioxygen pair (VO{sub 2}) and interactions involving atomic hydrogen.« less