Surface vacancy charging on semiconductors at nonzero temperatures

A theory for estimating ionization entropies of vacancies on semiconductor surfaces is developed, using Si(100)-(2×{}1) as a specific example. This theory helps to determine the most likely charge state at processing temperatures for a wide variety of semiconductors. For the dominant vacancy type on Si(100)-(2×{}1) (the divacancy), the most likely charge state shifts from neutral to negative above about 800 K. This transition is likely to affect the manifestation of phenomena such as nonthermal illumination-influenced diffusion.