Rigorous Surface-Potential Solution for Undoped Symmetric Double-Gate MOSFETs Considering Both Electrons and Holes at Quasi NonEquilibrium

This paper presents a rigorously-derived analytical solution of the Poisson equation with both electrons and holes in pure silicon, which is applied to the analysis of undoped symmetric double-gate transistors. An implicit surface-potential equation is obtained that can be solved by a second-order Newton-Raphson technique along with an appropriate initial guess. Within the assumption of holes at equilibrium that is being used in the existing literature, the new results, when compared with the models based on one carrier, reveal that missing the other carrier in the formulation results in a singularity in the gate capacitance exactly at flatband, which may give trouble for high-frequency analysis, although the errors in surface potentials are below the nano-volt range for all gate voltages. However, the solution without assuming constant hole imref, as presented in this paper for the first time, further pinpoints the inadequacy in existing theories of surface-potential solutions in double-gate MOSFETs with undoped thin bodies, although its application to transport solutions of terminal current/charge models depends highly on the type of source/drain structures and contacts.

[1]  Adelmo Ortiz-Conde,et al.  The foundation of a charge-sheet model for the thin-film MOSFET , 1988 .

[2]  C. Sah,et al.  The effects of fixed bulk charge on the characteristics of metal-oxide-semiconductor transistors , 1966 .

[3]  M. Wong,et al.  Analytical solutions to the one-dimensional oxide-silicon-oxide system , 2003 .

[4]  C. Sah,et al.  Effects of diffusion current on characteristics of metal-oxide (insulator)-semiconductor transistors☆ , 1966 .

[5]  A. R. Boothroyd,et al.  MISNAN-a physically based continuous MOSFET model for CAD applications , 1991, IEEE Trans. Comput. Aided Des. Integr. Circuits Syst..

[6]  J.J. Liou,et al.  A Review of Core Compact Models for Undoped Double-Gate SOI MOSFETs , 2007, IEEE Transactions on Electron Devices.

[7]  Yuan Taur,et al.  Analytic solutions of charge and capacitance in symmetric and asymmetric double-gate MOSFETs , 2001 .

[8]  R. Rios,et al.  A continuous compact MOSFET model for fully- and partially-depleted SOI devices , 1998 .

[9]  Y. Taur An analytical solution to a double-gate MOSFET with undoped body , 2000 .

[10]  Man Wong,et al.  Analytical I-V relationship incorporating field-dependent mobility for a symmetrical DG MOSFET with an undoped body , 2006 .

[12]  D. Flandre,et al.  Modeling of ultrathin double-gate nMOS/SOI transistors , 1994 .

[13]  Sah C-T,et al.  A History of MOS Transistor Compact Modeling , 2005 .

[14]  Adelmo Ortiz-Conde,et al.  Long-channel silicon-on-insulator MOSFET theory , 1992 .

[15]  Robert H. Kingston,et al.  Calculation of the Space Charge, Electric Field, and Free Carrier Concentration at the Surface of a Semiconductor , 1955 .

[16]  A. Ortiz-Conde,et al.  Analytic solution of the channel potential in undoped symmetric dual-gate MOSFETs , 2005, IEEE Transactions on Electron Devices.

[17]  Man Wong,et al.  On the threshold Voltage of symmetrical DG MOS capacitor with intrinsic silicon body , 2004 .

[18]  R. F. Steinberg,et al.  Analysis of double-gate thin-film transistor , 1967 .

[19]  Xing Zhou,et al.  Explicit Compact Surface-Potential and Drain-Current Models for Generic Asymmetric Double-Gate Metal–Oxide–Semiconductor Field-Effect Transistors , 2007 .