Thermal behavior of hydrogen molecules trapped by multivacancies in silicon

We have investigated the thermal behavior of hydrogen molecules trapped by multivacancies in crystalline silicon by performing thermal annealing. The hydrogen molecules had two Raman components with different annealing stages. Their activation energies for annihilation were 0.7 +/- 0.3 and 0.5 +/- 0.2eV for the main component and the shoulder, respectively. The former was attributed to the potential barrier for a hydrogen molecule to escape from a multivacancy trap, and the latter to move from a metastable site around the multivacancy trap to the most stable site. Annealing at 610 degreesC suggested that relatively large multivacancies such as V-6 and V-10 are possible trapping centers of the hydrogen molecules. (C) 2001 Elsevier Science B.V. All rights reserved.