A Simplified Model for Dynamic Depletion in Doped UTB-SOI/DG-FinFETs


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Compact modeling for doped-body MOSFETs, such as ultra-thin body (UTB) SOI and double-gate (DG) FinFETs, represents the most challenging task since it involves the Poisson’s solution with two boundary conditions, which is not available when the body doping cannot be ignored. A physically-scalable model in the complete range of operation should capture the surface-potential behaviors in accumulation, depletion, volume-inversion, and strong-inversion regions for any body-doping/thickness variations. It is even more difficult to model the so-called “dynamic depletion” (DD), in which partial to full depletion occurs at the drain end. In this paper, we extend our unified regional modeling (URM) approach, which has demonstrated scalable depletion to volume-inversion for any body doping/thickness, to modeling the DD effect. The “full-depletion” (FD) condition is reached when the sum of the depletion widths due to the two gates at the source end is equal to the body thickness. The same condition is applied to the drain end, which determines the DD condition. In this way, the FD/DD effects can be modeled by the simple full-depletion approximation. Results of the modeled surface-potential and gate-capacitance are demonstrated with complete scalability over body doping, thickness, and drain voltage, and validated with numerical data.

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Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2012: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational (Volume 2)
Published: June 18, 2012
Pages: 784 - 787
Industry sector: Sensors, MEMS, Electronics
Topic: Compact Modeling
ISBN: 978-1-4665-6275-2