Authors: X. Zhou
Affilation: Nanyang Technological University, Singapore
Pages: 726 - 731
Keywords: compact model (CM), double-gate (DG), gate-all-around (GAA), MOSFET, silicon nanowire (SiNW), ultrathin body (UTB) SOI, unified regional modeling (URM), Xsim
This paper presents a unified compact model (Xsim) for bulk/SOI MOSFETs, double-gate (DG) FinFETs, and gate-all-around (GAA) silicon-nanowires (SiNWs) that has been under development over the past 13 years. One key feature of the model is complete scalability with body doping and thickness, encompassing conventional bulk and partially-depleted (PD) SOI and emerging fully-depleted (FD) ultrathin body (UTB) SOI and DG/GAA FinFETs/SiNWs. The single core model is achieved with the unified regional modeling (URM) approach for the surface potential in all regions of operation, with body doping ranging from very high to low and undoped (pure Si). Some unique features that do not appear in other contemporary compact models include: ground-reference for floating-body (FB) SOI and DG/GAA devices with complete symmetry and physical modeling of asymmetric source/drain (S/D) without swapping S/D terminal polarities for Vds changing signs; gate-bias dependent S/D series resistance in all regions; velocity-overshoot modeling with the electron-temperature gradient term added to the conventional drift-diffusion formalism; seamless transition from depletion to volume/strong inversion for all ranges of body doping and thickness. Other major modeled effects include: vertical/lateral nonuniform doping; longitudinal/transverse-field mobility; quasi-2D solution for drain-induced barrier lowering (DIBL) and velocity saturation/overshoot; poly-gate accumulation/depletion/inversion effect (PAE/PDE/PIE); quantum-mechanical effect (QME); short-channel intrinsic/extrinsic charge model with URM of surface potential. The Xsim model has also been extended to strained-Si/SiGe channel and dopant-segregated Schottky-barrier (SB) MOSFETs, as well as physical modeling of interface traps for reliability and statistical-CM for variation and mismatch studies. The model has a small set of parameters (< 40) that requires minimum data and one or two-iteration parameter extraction. The ultimate goal of the Xsim model is for unification of MOSFET compact models with various gate, body, as well as source/drain structures and dimensions in one unified core framework for simulating and designing integrated circuits in future generation technologies.
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