A theory for estimating ionization entropies of vacancies on semiconductor surfaces was developed, using Si(100)-(2x1) 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)-(2x1) (the divacancy), the most likely charge state shifts from neutral to negative above about 800K. This transition was likely to affect the manifestation of phenomena such as non-thermal illumination-influenced diffusion.

Surface Vacancy Charging on Semiconductors at Non-Zero Temperatures. K.Dev, E.G.Seebauer: Physical Review B, 2003, 67[3], 035312 (4pp)