title: Brain-like associative learning using a nanoscale non-volatile phase change synaptic device array.
abstract: Recent advances in neuroscience together with nanoscale electronic device technology have resulted in huge interests in realizing brain-like computing hardwares using emerging nanoscale memory devices as synaptic elements. Although there has been experimental work that demonstrated the operation of nanoscale synaptic element at the single device level, network level studies have been limited to simulations. In this work, we demonstrate, using experiments, array level associative learning using phase change synaptic devices connected in a grid like configuration similar to the organization of the biological brain. Implementing Hebbian learning with phase change memory cells, the synaptic grid was able to store presented patterns and recall missing patterns in an associative brain-like fashion. We found that the system is robust to device variations, and large variations in cell resistance states can be accommodated by increasing the number of training epochs. We illustrated the tradeoff between variation tolerance of the network and the overall energy consumption, and found that energy consumption is decreased significantly for lower variation tolerance.
authors.affiliation: Department of Electrical Engineering, Stanford University Stanford, CA, USA.
authors.forename: Sukru B
authors.initials: SB
authors.lastname: Eryilmaz
authors.affiliation: Department of Bioengineering, University of Pennsylvania Philadelphia, PA, USA.
authors.forename: Duygu
authors.initials: D
authors.lastname: Kuzum
authors.affiliation: Department of Electrical Engineering, Stanford University Stanford, CA, USA.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Jeyasingh
authors.affiliation: IBM Research, T. J. Watson Research Center Yorktown Heights, NY, USA.
authors.forename: SangBum
authors.initials: S
authors.lastname: Kim
authors.affiliation: IBM Research, T. J. Watson Research Center Yorktown Heights, NY, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: BrightSky
authors.affiliation: IBM Research, T. J. Watson Research Center Yorktown Heights, NY, USA.
authors.forename: Chung
authors.initials: C
authors.lastname: Lam
authors.affiliation: Department of Electrical Engineering, Stanford University Stanford, CA, USA.
authors.forename: H-S Philip
authors.initials: HS
authors.lastname: Wong
keywords: associative learning; cognitive computing; device variation; neural network; neuromorphic computing; phase change memory; spike-timing-dependent-plasticity; synaptic device
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