Ag/HfO2 based threshold switch with extreme non-linearity for unipolar cross-point memory and steep-slope phase-FETs

Abstract

We demonstrate a novel Ag/HfO2 based threshold switch (TS) with a selectivity∼107, a high ON-state current (Ion) of 100 μA, and ∼10pA leakage current. The thresholding characteristics of the TS result from electrically triggered spontaneous formation and rupture of an Ag filament which acts an interstitial dopant in the HfO2 insulating matrix. Further, we harness the extreme non-linearity of the TS in (1) Selectors for Phase Change Memory (PCM) based cross-point memory. We show through array level simulations of a 1024kb memory, a read margin of 28% and write margin of 32% for a leakage power of <25μW (V/3 scheme); (2) A steep-slope sub-kT/q Phase-FET, experimentally demonstrating a switching-slope (SS) of 3mV/decade (over 5 orders of Ids), and >10x Ion improvement over the conventional FET (at iso-Ioff) at T=90C (50x at T=25C); making this a promising TS for both emerging memory, and steep-slope transistor applications.