Statistical modeling of V _th distribution in ovonic threshold switches based on physical switching models

Abstract

This paper discusses the statistical modeling of the Vth distribution of the ovonic threshold switch, a key component of high-speed, high-capacity storage-class memory. Based on three representative switching mechanisms—thermal runaway model, physically based electrical model, and two-state defect model—we propose a distribution function that explains Vth variation and a method for estimating and judging it. Through Monte Carlo simulations and analytical analysis of the distribution function, we examined the relationship between the segment Vth distribution and the Vth minimum distribution considering the chip-level scaling. The latter distribution approaches the Weibull distribution, but its convergence speed differs.