The Se was doped into material pre-doped with B, Ga, Al or In. The Se acted as a double donor, and paired with all of the dopants to give a donor level at Ec-0.2eV. An additional donor level at Ec-0.3eV was attributed to the first ionization level of Se in Si. Diffusion measurements at between 800 and 1250C showed that the diffusion coefficient of Se in Si was given by:

D(cm2/s) = 2.47 x 100exp[-2.84(eV)/kT]

Defect Pairing Diffusion, and Solubility Studies in Selenium-Doped Silicon. H.R.Vydyanath, J.S.Lorenzo, F.A.Kroger: Journal of Applied Physics, 1978, 49[12], 5928-37