The thermal formation of P mono-vacancies was studied (using scanning tunnelling microscopy) as a function of time, at temperatures ranging from 293 to 480K, on (110) surfaces. It was found that the formation rate of the P vacancies increased up to 435K. At temperatures above 435K, both the vacancy formation rate and the maximum vacancy concentration decreased. The highest vacancy concentration was 5 x 1012/cm2. Annealing the samples at temperatures above 480K reduced the vacancy concentration to the levels which were observed at room temperature. The results were explained in terms of 2 activated mechanisms with differing rates. These were thermal vacancy plus adatom pair formation (with subsequent desorption of P from the surface), and anion out-diffusion from the bulk.

M.Heinrich, P.Ebert, M.Simon, K.Urban, M.G.Lagally: Journal of Vacuum Science and Technology A, 1995, 13[3], 1714-8