Self-interstitial–hydrogen complexes in silicon

Abstract

The vibrational properties of interstitial silane (SiH 4) i and silyl (SiH 3) i molecules in crystalline silicon are calculated using a first-principle, cluster based, spin-polarised local-density method. The Si-H stretch modes are found to be red-shifted by ∼ 300 cm −1 from those of the isolated molecule which lie around 2200 cm −1. These results refute recent suggestions that modes observed around 2200 cm −1 , and previously assigned to hydrogenated vacancy defects, are due to these interstitial molecules.

Si-H clusters, defects, and hydrogenated silicon

“…For defect structures in Si the frequencies determined by Fourier transform infrared spectroscopy 17 48 who calculated that the stretch modes of interstitial silane (SiH 4 ) were lowered by 300 cm Ϫ1 from those of the isolated molecule (ϳ2000 cm Ϫ1 , see Table II͒. In Fig.…”

Si isotopic structure of the infrared absorption of the fully hydrogenated vacancy in silicon

“…Therefore, Mukashev et al 4 concluded that the 2223 cm −1 LVM was due to VH 4. This attribution is substantiated by ab initio calculations of the frequency 7 In addition to the above-discussed triply degenerate T 2 mode, a center like VH 4 or i-SiH 4 also displays a singly degenerate breathing stretch mode with A 1 symmetry, where the four Si-H bonds of the center vibrate in phase. Such a mode is infrared (IR)-inactive, but Raman-active.…”

Wafer Processing

“…They are transformed into spherical voids by annealing at around 1100 C in a hydrogen atmosphere [136][137][138][139][140]. Experimentally, different techniques have been explored over the years.…”