Fault-Tolerant Fault-Tolerant Techniques and Techniques and

Nanoelectronic DevicesNanoelectronic DevicesAndy HillAndy Hill

CH E 5480 995CH E 5480 995

AbstractAbstract Proposed nanocomputers offer Proposed nanocomputers offer

faster, more powerful computingfaster, more powerful computing Problems expectedProblems expected

– High manufacturing defect rateHigh manufacturing defect rate– Transient errorsTransient errors

Two possible solutionsTwo possible solutions– Increase manufacturing efficiencyIncrease manufacturing efficiency– Increase device’s capacity for defectsIncrease device’s capacity for defects

Abstract (cont’d)Abstract (cont’d) Most nanoelectronic device research Most nanoelectronic device research

today is devoted to reducing the size today is devoted to reducing the size of devicesof devices

Fault-tolerant technique research Fault-tolerant technique research shows that the reconfiguration method shows that the reconfiguration method is:is:– Can handle the highest defect rateCan handle the highest defect rate– Cannot handle the current defect rateCannot handle the current defect rate– May be impracticalMay be impractical

IntroductionIntroduction First computer invented had one First computer invented had one

function – to solve linear equationsfunction – to solve linear equations Always a push to be faster, more Always a push to be faster, more

powerfulpowerful Other technologies would aid Other technologies would aid

tremendously from more powerful tremendously from more powerful computers computers – MilitaryMilitary– Artificial IntelligenceArtificial Intelligence– Medical / BiologicalMedical / Biological

Literature ReviewLiterature Review Fault-tolerant techniques have been Fault-tolerant techniques have been

studied for over half a centurystudied for over half a century Research focused on application of Research focused on application of

technique technique Current research focused on Current research focused on

techniques for chips with 10techniques for chips with 1012 12 devices devices in 1 square cmin 1 square cm

Lit Review (cont’d)Lit Review (cont’d) Nanoelectronic device research Nanoelectronic device research

mainly focused on producing mainly focused on producing molecular scale devicesmolecular scale devices

Limited research on the production of Limited research on the production of those devicesthose devices

Theoretical BackgroundTheoretical Background Main fault-tolerant techniquesMain fault-tolerant techniques

– Redundancy (RMR, CTMR)Redundancy (RMR, CTMR)– NAND multiplexingNAND multiplexing– ReconfigurationReconfiguration

RedundancyRedundancy

R-fold (RMR) redundancy (R-fold (RMR) redundancy (leftleft) is a function of cascaded triple ) is a function of cascaded triple (CTMR) redundancy ((CTMR) redundancy (rightright))

[1]

Multiplexing / ReconfigMultiplexing / Reconfig NAND multiplexingNAND multiplexing

– Complex system utilizing majority gates Complex system utilizing majority gates and NAND logicand NAND logic

– Adaptive to decreasing manufacturing Adaptive to decreasing manufacturing effficiencyeffficiency

ReconfigurationReconfiguration– Units not working are detectedUnits not working are detected– Cluster reconfigured accordinglyCluster reconfigured accordingly

Current ResearchCurrent Research Research comparing techniques Research comparing techniques

shows reconfiguration can adapt to shows reconfiguration can adapt to highest defect rates, but may be highest defect rates, but may be impracticalimpractical [1]

Current research (cont’d)Current research (cont’d) Nanoelectronic devices being Nanoelectronic devices being

researched are 100 to 1000 times researched are 100 to 1000 times smaller than current devicessmaller than current devices

[2]

Future DirectionsFuture Directions Continue research of techniques Continue research of techniques

specific to nano-scaled devicesspecific to nano-scaled devices– Determine practicality of reconfigurationDetermine practicality of reconfiguration

Continue research developing Continue research developing nanoelectronic devicesnanoelectronic devices

Research the efficiency of mass Research the efficiency of mass producing devicesproducing devices

ReferencesReferences[1] - K Nikolic, A Sadek and M Forshaw [1] - K Nikolic, A Sadek and M Forshaw

2002 Fault-tolerant techniques for 2002 Fault-tolerant techniques for nanocomputersnanocomputers NanotechnologyNanotechnology 1313 357-362 357-362

[2] - Goldhaber-Gordon D. [2] - Goldhaber-Gordon D. et al.et al. 1997 1997 Overview of Nanoelectronic Devices Overview of Nanoelectronic Devices Proceedings of the IEEE Proceedings of the IEEE 8585 (4) (4)