UltralowPower Pseudospintronic Devices via Excito

Authors: Xuehao Mou Leonard Franklin Register Sanjay Kumar Banerjee

Publish Date: 2015

Volume: , Issue: , Pages: 31-91

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Abstract

“Pseudospintronic” device concepts novel “beyondCMOS” device proposals targeted toward revolutionizing the current semiconductor technology based on MOSFETs and CMOS logic are addressed in detail These pseudospin devices include the voltagecontrolled Bilayer pseudoSpin FieldEffect Transistor BiSFET and the currentcontrolled Bilayer pseudoSpin Junction Transistor BiSJT MOSFETs are confronted by the intractable physics of thermionic emission and resulting sourcetodrain leakage that limits voltage scaling As a result CMOS faces an “energy crisis” much as the one faced by bipolar junction transistorbased logic that led to CMOS As for many other beyondCMOS concepts these pseudospintronic devices are based on a completely different physics of switching potentially allowing much lower voltage and power operation These pseudospintronic device concepts employ possible roomtemperature interlayer electron–hole exciton condensates between two dielectrically separated layers of twodimensional 2D materials for subthermal voltage subk B T/q switching specifically from a nearly shorted interlayer conductance state to a highly resistive interlayer conductance state with increasing interlayer voltage These collective exciton states with their “whichlayer” degree of freedom are somewhat analogous to collective spin states in magnets which is the origin of the “pseudospintronics” moniker Device performance in the presence of such condensates is the primary focus of this work the possibility of roomtemperature condensates itself is addressed by other research still in progress We begin with a discussion of the underlying physics Graphenebased pseudospintronic systems then are analyzed using quantum transport simulations incorporating the nonlocal exchange interaction However the essential transport physics should be much the same for other 2D material systems including transition metal dichalcogenides for which the realization of the condensate may be easier The BiSFET and BiSJT device concepts are presented in detail and basic logic gate designs are illustrated for each Compact device models are developed and SPICElevel circuit simulations are performed to demonstrate possible switching energies on the scale of or below a tenth of an attojoule well below even endoftheroadmap CMOS However like many other beyondCMOS concepts these devices remain concepts without solid experimental embodiments The fabrication concerns of such novel devices are also discussed along with recent experimental progressThis work was supported by the South West Academy of Nanoelectronics SWAN which in turn is supported by the Semiconductor Research Corporation SRC and the National Institute of Standards and Technology NIST through the Nanoelectronics Research Initiative NRI

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