IMPURITY DIFFUSION DURING RTA.
Enhanced dopant diffusion during rapid thermal annealing (RTA) depends whether the following physical phenomena occur individually or in combination: (1) amorphization of the Si, (2) damage-induced dislocation formation, (3) damage annealing, (4) self-interstitial trapping and (5) solubility enhancement. RTA of B in crystalline or preamorphized Si presents different environments for enhanced diffusion. In preamorphized Si, enhanced B diffusion is modeled as increased B solubility following solid phase epitaxy (SPE). In addition, a different intrinsic diffusivity is observed which corresponds to B diffusion in preamorphized Si. Anomalous diffusion of P and As from high dose implants can be modeled with the same mechanism - self-interstitial trapping following SPE.
