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

Abstract

This paper discusses the statistical modeling of the V th distribution of an ovonic threshold switch, an integral component of high-speed, high-capacity storage-class memory. A distribution function that explains the V th variation and a method for estimating and judging it is proposed based on three representative switching mechanisms—thermal runaway model, physically based electrical model, and two-state defect model. We examined the relationship between the segment V th distribution and V th minimum distribution is examined by considering chip-level scaling in Monte Carlo simulations and analytical analysis of the distribution function. The latter distribution approaches the Weibull distribution; however, its convergence speed differs.