STATE: A Test Structure for Rapid Prediction of Resistive RAM Electrical Parameter Variability.

Resistive RAM (RRAM) design optimization and reliability monitoring is essential not only to gain market share in the highly competitive emerging memory sector, but also to enable future high-capacity and power-efficient brain-inspired systems, beyond the capabilities of today's hardware. Common problems with RRAM are related to high variability in operating conditions and low yield. Although research has taken steps to resolve these issues, variability remains a major hurdle for the wide spread of the technology. In this paper, a novel test structure consisting of an array of non-addressable 1T-1R RRAM memory cells with parallel connection of all memory elements is introduced. The test structure can be used as a powerful tool for process variation monitoring during a new process technology introduction and also for marginal cell populations detection during process maturity. The test structure is designed to measure RRAM parameters of interest based on a simple measurement methodology: from the transfer characteristic measured under the select transistor clamping bias, it is possible to obtain accurate information on the RRAM switching parameters as well as the ON/OFF resistance values.