A Stable Low Leakage Power SRAM with Built-In Read/Write-Assist Scheme using GNRFETs for IoT Applications

Abstract

Design of circuits using graphene nanoribbon field-effect transistors (GNRFETs), as promising next-generation devices, can improve total performance of a chip due to offering excellent properties. However, GNRFETs are in the early stage of design, and the studies of process-voltage-temperature (PVT) variations on their performance are very crucial. Here, we aimed to design, simulate, and evaluate a novel stable fully differential 12T (SFD12T) SRAM using GNRFETs under PVT variations. Simulation results in 16-nm GNRFET technology at 0.5 V show that the proposed design improves read stability/writability by 2.11×/1.09× compared to fully differential 8T (FD8T: as a basic cell) due to using built-in read/write-assist scheme, which forces the ‘0’ storing node to ground during a read operation and cuts pull-down path off during a write operation, respectively. An improvement of at least 4.79% (18.55% compared to FD8T) in leakage power is achieved due to stacking of transistors. The fourth-best read/write energy among eight studied SRAMs is related to the proposed design. In addition, it can support the bit-interleaving architecture because it eliminates half-select disturbance issues. Generally, the proposed design is the best SRAM from the figure of merit (FOM) point of view, so it can be an optimal choice for Internet-of-Things applications.

An ultra‐low power and energy‐efficient ternary Half‐Adder based on unary operators and two ternary 3:1 multiplexers in 32‐nm GNRFET technology

“…Figures 1(A) and (B) show the two‐dimensional (2‐D) and three‐dimensional (3‐D) views of a GNRFET structure, respectively 33,34 . In a GNRFET, multiple GNRs have a parallel connection to improve the drive strength and to form wide, conducting contacts 12 .…”

“…The channel region of a GNRFET has intrinsic GNRs while the drain and source contacts have GNRs heavily doped with doping fraction ( ) 12 . Graphene is turned into a 1‐D GNR with sub‐10 nm width to have a bandgap and become semiconducting to use as a channel material 33,35 . Depending on the edge form, a GNR would have either metallic or semiconducting properties 36–38 .…”

“…A Structure of a GNRFET with multiple AGNRs in the channel region, (A) 2‐D view 33 and (B) 3‐D view 34 …”

“…Figures 1(A) and (B) show the two-dimensional (2-D) and three-dimensional (3-D) views of a GNRFET structure, respectively. 33,34 In a GNRFET, multiple GNRs have a parallel connection to improve the drive strength and to form wide, conducting contacts. 12 The channel region of a GNRFET has intrinsic GNRs while the drain and source contacts have GNRs heavily doped with doping fraction (f dop ).…”

“…12 Graphene is turned into a 1-D GNR with sub-10 nm width to have a bandgap and become semiconducting to use as a channel material. 33,35 Depending on the edge form, a GNR would have either metallic or semiconducting properties. [36][37][38] GNR with zigzag edges (ZGNR) is metallic while GNR with armchair edges (AGNR) is semiconducting.…”