Shallow thermal donors in silicon: The roles of Al, H, N, and point defects

Three families of shallow thermal donors have been identified in annealed C zochralski silicon from measurements of their infrared electronic transitio ns using Fourier transform spectroscopy. Donors produced in Al-doped Si inc orporate an Al impurity; centers produced in hydrogenated material contain an H (or D) atom; a third set of donors labeled STD(X)N produced in nitrida ted or irradiated pre-hydrogenated samples may incorporate a lattice vacanc y rather than a nitrogen atom. A critical review of the literature is made and some rationalization has been effected. Comments are included about the formation of donor centers following anneals of heavily damaged neat-zone Si that also contains hydrogen.