the combination of said annealing steps creating a diffusion profile having a sharp delineation in said structure and permitting {HEAD ~ a deeper penetration} of the diffusion profile compared to the penetration depth obtainable employing exclusively the second of said annealing steps at a given temperature due to {TAIL ~ the presence} of said surface diffusion profile 
the combination of said annealing steps creating a diffusion profile having a sharp delineation in said structure and permitting { HEAD ~ a deeper penetration } of the diffusion profile compared to the penetration depth obtainable employing exclusively the second of said annealing steps at a given temperature due to { TAIL ~ the presence } of said surface diffusion profile
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH