Taiwan Semiconductor Manufacturing Company Limited
CROSS-POINT MEMORY-SELECTOR COMPOSITE PILLAR STACK STRUCTURES AND METHODS OF FORMING THE SAME

Abstract:

A via-level dielectric material layer is formed over a first dielectric material layer embedding a first conductive structure. A via cavity is formed through the via-level dielectric material layer. A least one straight sidewall vertically extends from a closed upper periphery of the via cavity at a top surface of the via-level dielectric material layer to a closed lower periphery of the via cavity that is adjoined to a top surface of the first conductive structure. A pillar stack structure is formed in the via cavity by sequentially forming a set of material portions containing a lower pillar structure and an upper pillar structure. The lower pillar structure and the upper pillar structure include a selector material pillar and a memory material pillar. A second conductive structure may be formed on a top surface of the pillar stack structure. The pillar stack structure may be used in an array configuration.