Sigmoid Probabilistic Bits Using SiOx Threshold Switching Devices for Probabilistic Computing

초록

We present probabilistic bits(p-bits)implemented using a simple and fabrication-friendly Ti/SiOx/Ti stack for probabilistic computing. Sputter-deposited thin SiOx films (<10 nm) exhibit threshold switching (TS) behavior under dc characterization, producing continuous output voltage (Vout) oscillations in response to a given input voltage (Vin) pulse. Whena chemically reactive Ti scavenging layer is introduced, nonuniform TS properties are observed, resulting in switching voltage (or resistance) variability and unexpected oscillation failures. Consequently, Voutoscillations begin to be detected in the form of random spikes, emulatingthe probability of representing data as "1" (P1). Notably,we demonstrate that when the SiOx layer is sandwiched between Ti scavengers at both interfaces, the value ofP1can be controlled between 0 and 1 in an inverselyproportional relationship toVin. This sigmoidP1curvederived from Ti/SiOx/Ti p-bits plays a crucial role inexecuting simulated annealing (SA) algorithms. Thiscapability is validated through MATLAB simulations, where the approach is applied to solve vehicle routing problems(VRPs) by identifying optimal solutions

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