One-Pulse-Programmable Multi-Level PCM/Selector Cross-Point Memory for 20 nm Half Pitch and Beyond

We demonstrated, for the first time, a multi-level phase change memory/selector cell which can be operated without initialization or iterative verify, showing the potential for future cost-effective storage-class memory applications where both high density and low latency are essential. We found optimal thermal and composition design enabled to form distinct middle resistance state, in which crystalline and amorphous co-exist and were placed at designed positions. Multi-level programming was achieved by one single pulse without any additional operation, and it was stable over >10
⁷
cycles with sufficient memory window. Furthermore, we fabricated and demonstrated PCM/selector cross-point memory array with half-pitch of 20 nm. Thermal simulation showed the one-pulse multi-level operation is feasible in cross-point array with 20 nm half-pitch and beyond.