Comprehensive Optimization of Dual Threshold Independent-Gate FinFET and SRAM Cells

Independent-Gate (IG) FinFET is a promising device in circuit applications due to its two separated gates, which can be used independently. In this paper, we proposed a comprehensive method to optimize the Dual Threshold (DT) IG FinFET devices by carrying out modulations for the gate electrode work function, oxide thickness, and silicon body thickness. Titanium nitride (TiNx) is used as the tunable work function gate electrode for good performances. The thicknesses of the gate oxide and silicon body are swept by TCAD simulations to obtain the appropriate values. The verification simulation of the optimized transistors shows that the DT IG FinFETs can realize merging parallel and series transistors, respectively, and the current characteristics of the transistors are improved significantly. By extracting the BSIM-IMG model parameters, we can simulate the circuits composed of the proposed DT IG FinFET by using HSPICE with BSIM-IMG model. As practical examples, we optimized two novel 7T SRAM cells using DT IG FinFETs. HSPICE simulation results indicate that the new SRAM cells obtain higher write margin and read static noise margin with lower leakage power consumption than the other implementations.

[1]  E. Harrell,et al.  A physical short-channel threshold voltage model for undoped symmetric double-gate MOSFETs , 2003 .

[2]  C. Tretz,et al.  High-Density Reduced-Stack Logic Circuit Techniques Using Independent-Gate Controlled Double-Gate Devices , 2006, IEEE Transactions on Electron Devices.

[3]  Jean-Pierre Colinge,et al.  FinFETs and Other Multi-Gate Transistors , 2007 .

[4]  Huishan Yang,et al.  Novel SRAM cells using dual-threshold independent-gate FinFETs , 2017, 2017 IEEE 17th International Conference on Nanotechnology (IEEE-NANO).

[5]  R. Ribas,et al.  New challenges on Independent Gate FinFET Transistor Network Generation , 2014 .

[6]  Chenming Calvin Hu,et al.  Modern Semiconductor Devices for Integrated Circuits , 2009 .

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

[8]  Jianping Hu,et al.  Optimization of dual-threshold independent-gate FinFETs for compact low power logic circuits , 2016, 2016 IEEE 16th International Conference on Nanotechnology (IEEE-NANO).

[9]  Anna W. Topol,et al.  Stable SRAM cell design for the 32 nm node and beyond , 2005, Digest of Technical Papers. 2005 Symposium on VLSI Technology, 2005..

[10]  Chenming Hu,et al.  Modeling 20-nm Germanium FinFET With the Industry Standard FinFET Model , 2014, IEEE Electron Device Letters.

[11]  Babak Falsafi,et al.  A case for asymmetric-cell cache memories , 2005, IEEE Transactions on Very Large Scale Integration (VLSI) Systems.

[12]  Zheng Guo,et al.  FinFET-based SRAM design , 2005, ISLPED '05. Proceedings of the 2005 International Symposium on Low Power Electronics and Design, 2005..

[13]  E. Suzuki,et al.  Investigation of the TiN Gate Electrode With Tunable Work Function and Its Application for FinFET Fabrication , 2006, IEEE Transactions on Nanotechnology.

[14]  G. Paasch,et al.  A Modified Local Density Approximation. Electron Density in Inversion Layers , 1982 .

[15]  Takashi Matsukawa,et al.  Spatial variation of the work function in nano-crystalline TiN films measured by dual-mode scanning tunneling microscopy , 2014 .

[16]  Narayanan Vijaykrishnan,et al.  Independently-Controlled-Gate FinFET 6T SRAM Cell Design for Leakage Current Reduction and Enhanced Read Access Speed , 2014, 2014 IEEE Computer Society Annual Symposium on VLSI.

[17]  Kartik Mohanram,et al.  Novel dual-Vth independent-gate FinFET circuits , 2010, 2010 15th Asia and South Pacific Design Automation Conference (ASP-DAC).

[18]  B. Iniguez,et al.  Two-Dimensional Analytical Threshold Voltage and Subthreshold Swing Models of Undoped Symmetric Double-Gate MOSFETs , 2007, IEEE Transactions on Electron Devices.

[19]  Felipe S. Marques,et al.  Exploring independent gates in FinFET-based transistor network generation , 2014, 2014 27th Symposium on Integrated Circuits and Systems Design (SBCCI).

[20]  Jörgen Olsson,et al.  Variable work function in MOS capacitors utilizing nitrogen-controlled TiNx gate electrodes , 2004 .

[21]  Yuan Taur.  An analytical solution to a double-gate MOSFET with undoped body , 2000, IEEE Electron Device Letters.

[22]  K. Endo,et al.  Independent-Double-Gate FinFET SRAM for Leakage Current Reduction , 2009, IEEE Electron Device Letters.

[23]  Kartik Mohanram,et al.  Dual-$V_{th}$ Independent-Gate FinFETs for Low Power Logic Circuits , 2011, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems.

[24]  InGaAs FinFET modeling using industry standard compact model BSIM-CMG , 2014 .

[25]  D. Fried,et al.  Improved independent gate N-type FinFET fabrication and characterization , 2003, IEEE Electron Device Letters.