Evidence for a new class of defects in highly n-doped Si: donor-pair-vacancy-interstitial complexes.
Electron channeling experiments performed on individually scanned, single columns of atoms show that in highly n-type Si grown at low temperatures the primary electrically deactivating defect cannot belong to either the widely accepted class of donor-vacancy clusters or a recently proposed class of donor pairs. First-principles calculations suggest a new class of defects consisting of two dopant donor atoms near a displaced Si atom, which forms a vacancy-interstitial pair. These complexes are consistent with the present experimental results, the measured open volume of the defects, the observed electrical activity as a function of dopant concentration, and the enhanced diffusion of impurities in the presence of deactivated dopants.
Voyles
P M
PM
Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974, USA. voyles@engr.wisc.edu
Chadi
D J
DJ
Citrin
P H
PH
Muller
D A
DA
Grazul
J L
JL
Northrup
P A
PA
Gossmann
H-J L
HJ