Si Incorporation Into AsSeGe Chalcogenides for High Thermal Stability, High Endurance and Extremely Low $\mathrm{V}_{\mathrm{th}}$ Drift 3D Stackable Cross-point Memory : IBM/Macronix PCRAM Joint Project

Abstract

By incorporating Si into AsSeGe system, we demonstrate a 3D stackable OTS+PCM memory in a 1k by 1k cross-point memory array with extremely low $\mathrm{V}_{\mathrm{tS}}$ drift (~0V after 3 days from programming), wide $\mathrm{V}_{\mathrm{tS}}/\mathrm{V}_{\mathrm{tR}}$ window (>2V main distribution memory window), high endurance (>2E11 cycles), excellent $\mathrm{I}_{\mathrm{OFF}}$ and thermal stability. So far, attempts to improve the thermal stability of AsSeGe system sacrifice $\mathrm{I}_{\mathrm{OFF}}$ and cycling endurance. We show that Si incorporation relaxes this trade-off and can greatly improve the thermal stability and cycling endurance while also achieving good $\mathrm{I}_{\mathrm{OFF}}$. In particular the $\mathrm{I}_{\mathrm{OFF}}$ of AsSeGeSi selector is improved over the AsSeGe system for films of 20 nm.