Title :
Low-Power Circuit Analysis and Design Based on Heterojunction Tunneling Transistors (HETTs)
Author :
Yoonmyung Lee ; Daeyeon Kim ; Jin Cai ; Lauer, I. ; Chang, Ly-Yu ; Koester, Steven J. ; Blaauw, D. ; Sylvester, Dennis
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Univ. of Michigan, Ann Arbor, MI, USA
Abstract :
The theoretical lower limit of subthreshold swing in mosfets (60 mV/decade) significantly restricts low-voltage operation since it results in a low ON -to- OFF current ratio at low supply voltages. This paper investigates extremely low-power circuits based on new Si/SiGe heterojunction tunneling transistors (HETTs) that have a subthreshold swing of . Device characteristics, as determined through technology computer aided design tools, are used to develop a Verilog-A device model to simulate and evaluate a range of HETT-based circuits. We show that an HETT-based ring oscillator (RO) shows a 9-19 times reduction in dynamic power compared to a CMOS RO. We also explore two key differences between HETTs and traditional mosfets, namely, asymmetric current flow and increased Miller capacitance, analyze their effect on circuit behavior, and propose methods to address them. HETT characteristics have the most dramatic impact on static random access memory (SRAM) operation and we propose a novel seven-transistor HETT-based SRAM cell topology to overcome, and take advantage of, the asymmetric current flow. This new HETT SRAM design achieves 7-37 times reduction in leakage power compared to CMOS.
Keywords :
Ge-Si alloys; SRAM chips; electronic engineering computing; elemental semiconductors; hardware description languages; integrated circuit design; low-power electronics; silicon; technology CAD (electronics); tunnel transistors; CMOS RO; MOSFET; ON-to-OFF current ratio; Si-SiGe; Verilog-A device model; asymmetric current flow; computer aided design tool; heterojunction tunneling transistor; increased Miller capacitance; low supply voltage; low-power circuit design analysis; low-voltage operation; power leakage reduction; ring oscillator; seven-transistor HETT-based SRAM cell topology; static random access memory operation; subthreshold swing limit; CMOS integrated circuits; Hardware design languages; Logic gates; MOSFETs; Random access memory; Tunneling; 7T SRAM; heterojunction tunneling transistors (HETT); low-power; tunneling transistor;
Journal_Title :
Very Large Scale Integration (VLSI) Systems, IEEE Transactions on
DOI :
10.1109/TVLSI.2012.2213103