A Compact Model Satisfying
Gummel Symmetry in Higher Order Derivatives and Applicable to Asymmetric
Guan Huei See, Student Member, IEEE, Xing Zhou, Senior
Member, IEEE, Karthik Chandrasekaran, Siau Ben Chiah, Zhaomin Zhu, Chengqing
Wei, Shihuan Lin, Guojun Zhu, and Guan Hui Lim, Student Member, IEEE
IEEE Transactions on Electron Devices,
55, No. 2, pp.
624-631, Feb. 2008.
(Manuscript received July 5, 2007; revised
October 15, 2007.)
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This paper presents a new concept for the MOSFET saturation voltages
at the drain and source sides referenced to bulk, and applies them to the
popularly used smoothing functions for the effective drain–source voltage
(Vds,eff). The proposed model not only builds in physically
all the terminal-bias variations, but is also extended to include source/drain
asymmetry in real devices in a single core compact model. The new
model resolves a key bottleneck in existing models for passing the Gummel
symmetry test (GST) in higher order derivatives, which has to be traded
off for the geometry-dependent Vds,eff smoothing parameter. The complete
drain-current model, including the effects of velocity saturation and overshoot
as well as source/drain series resistance, has also been reformulated with
the same “bulk-referencing” concept. It is shown that the proposed
model passes the GST in all higher order derivatives without any constraint
on the value of the smoothing parameter. It also demonstrates potential
extension to modeling asymmetric MOSFETs, which is becoming an important
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