The cross-point architecture for memory arrays is widely considered as one of the most attractive solutions for storage and memory circuits thanks to simplicity, scalability, small cell size, and consequently high density and low cost. Cost-scalable vertical 3-D cross-point architectures, in particular, offer the opportunity to challenge Flash memory with comparable density and cost. To develop scalable cross-point arrays, however, select devices with sufficient ON-OFF ratio, current capability, and endurance must be available.
This paper presents a select device technology based on volatile resistive switching withCu and Ag top electrode and silicon oxide (SiO x ) switching materials. The select device displays ultrahigh resistance window and good current capability exceeding 2 MAcm −2 . Retention study shows a stochastic voltage-dependent ON-OFF transition time in the 10 µs-1 ms range, which needs to be further optimized for fast memory operation in storage class memory arrays. Index Terms-Conductive bridge RAM (CBRAM), cross-point array, select device, silicon oxide, storage class memory, volatile switching.
I. INTRODUCTIONC ROSS-POINT arrays represent a promising architecture to compete with Flash memories in terms of density and bit cost. In a cross-point array, every memory element is located at the intersection between a row and a column electrode wire, therefore achieving a minimum device size of 4F 2 , where F is the minimum lithographic feature. Cross-point arrays were proposed for resistive switching (RS) memory (RRAM) [1]-[3] and phase change memory (PCM) [4], [5], both benefitting from a relatively large resistance window and