Effect of pressure on oxygen diffusion jump in Si: quantum-chemical simulations

✍ Scribed by Vasilii Gusakov; Leonid Murin

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 189 KB
• Volume: 340-342
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2003.09.272

✦ Synopsis

A theoretical modeling of the oxygen diffusivity in crystalline silicon both at normal and high hydrostatic pressure has been carried out using molecular mechanics, semiempirical and ab initio methods. It was established that the diffusion process of an interstitial oxygen atom (O i ) is controlled by the optimum configuration of three silicon atoms nearest to O i . The calculated values of the activation energy DE a ¼ 2:59 eV and pre-exponential factor D 0 ¼ 0:28 cm 2 s À1 are in good agreement with the experimental ones and for the first time described perfectly as an experimental dependence of the O i diffusion constant in the temperature range 350-1200 C. Hydrostatic pressure ðPp80 kbarÞ results in a linear decrease of the diffusion barrier ðq P DE a ðPÞ ¼ À4:38 Â 10 À3 eV kbar À1 Þ: The calculated pressure dependence of O i diffusivity agrees well with the pressure-enhanced initial growth of oxygen-related thermal donors.