depositing a diffusion source layer comprising the impurity species of Si or Ge on the surface of said structure in the presence of an source of As, P or {HEAD ~ Sb} heavily doping said {TAIL ~ layer} in the range of 5 to 20 by atomic percent, 
depositing a diffusion source layer comprising the impurity species of Si or Ge on the surface of said structure in the presence of an source of As , P or { HEAD ~ Sb } heavily doping said { TAIL ~ layer } in the range of 5 to 20 by atomic percent ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH