Design of content addressable memory cell using carbon nanotube field effect transistors

Abstract

This paper presents design and analysis of low voltage stable SRAM based 11-transistor high speed content addressable memory (CAM) unit using dual gate (DG) Schottky-barrier carbon nanotube field effect transistor (SB-CNTFET). The 8-transistor highly stable SRAM counterpart of CAM cell contains six p-type and two n-type dual gate SB-CNTFETs where the searching network adds three more p-type transistors. The circuit compatible model of dual gate SB-CNTFET operates steadily at 0.5 V power supply. The design is implemented with Si-MOSFET, MOSFET-like CNTFET and DG SB-CNTFET. For the proposed low voltage SRAM based DG SB-CNTFET CAM cell, we have achieved 120× lesser power-delay-product (PDP) during read operation, 845× lesser PDP during write operation and 407× lesser PDP during search operation compared to similar design using Si-MOSFET. The DG SB-CNTFET based CAM also shows ∼2× less PDP during read-write-search operations as compared to the MOSFET-like CNTFET based CAM cell.