Abstract
In recent years, VLSI technology develops rapidly. Portable and wearable electronics products demanding low power high density nonvolatile memory. Flash Memory, the mainstream NVM, faces high operating voltage and process scaling problems, so resistive random access memory shows great potential in advance NVM devices. This study proposed methods to improve the developmental issues of Contact Resistive Random Access Memory (CRRAM).The original CRRAM is fabricated by controlling RRAM thickness and contact size. Due to instability of contact hole etching rate, RRAM film could be non-uniform and affect yield rate. Backfill Contact Resistive Random Access Memory (BCRRAM) is proposed to solve this problem. A thin RRAM film is deposited into each contact hole by PECVD, instead. The BCRRAM can endure 1000k cycles and 85oC 2000hr baking without data alternation. Through experiment, the device proves no reliability concerns. BCRRAM is a unipolar RRAM. Over programming damage may occur during reset operation. Therefore, Incremental Step Pulse Programming (ISPP) is included to optimize SET/RESET cycles to improve BCRRAM endurance. The ratio of LRS/HRS is greater than 50X, with more than 1000k cycles.