Dopant diffusion model refinement and its impact on the calculation of reverse short channel effect

A couple of dopant diffusion models were examined and refined in terms of both diffusion profiles and simulation of device characteristics. The refinement included appropriate binding-energy values for dopant-defect pairs, electrical activation for arsenic, and the boundary condition for the interstitial-silicon. These are directly related to the quantitative simulation of the reverse short-channel effect (RSCE) for initially flat channel profile nMOSFETs. Source/drain implantation damage is the most crucial factor for the RSCE. For LDD devices, the calculation assuming a certain mid-range value for the coefficient representing the ratio of damage to arsenic dosage reproduced the measured threshold voltage rising quite well.