Atomistic 3D process/device simulation considering gate line-edge roughness and poly-Si random crystal orientation effects [MOSFETs]

Using newly developed simulation tools for the precise design of sub-100 nm MOSFETs, intrinsic statistical fluctuations in device characteristics were examined. Ion implantation and subsequent dopant diffusion/activation were simulated based on Monte Carlo procedures. 3D device simulations were performed based on the conventional drift-diffusion model in which electrostatic potential distributions were constructed from the long-range Coulombic components of individual discrete dopant atom potentials. Gate line-edge-roughness (LER) and random discrete dopant effects were incorporated in this simulation. Another possible source of fluctuation, i.e. gate poly-Si crystalline grain random orientation effects in conjunction with oblique halo implantation, was also examined. An atomistic approach to both 3D process and device simulations enabled us to closely examine the coupling effects of the significant sources of fluctuation, i.e. LER and random-discrete-dopant, in the context of practical fabrication processes.