A Regulated Sensing Solution based on a Self-Reference Principle for PCM+OTS Memory Array

J Gasquez (1) , B Giraud (2) , P Boivin (3) , Y Moustapha-Rabault (1) , V Della Marca (4) , J P Walder (4) , J M Portal (4)

1 ST-CROLLES - STMicroelectronics [Crolles]
2 LFIM - Laboratoire Fonctions Innovantes pour circuits Mixtes
3 ST-ROUSSET - STMicroelectronics [Rousset]
4 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence

Phase change memory (PCM) device associated with Ovonic Threshold Switch (OTS) selector is a proven solution to fill the gap between DRAM and mass storage. This technology also has the potential to be embedded in a high-end microcontroller. However, programming and reading phases efficiency is directly linked to the selector's leakage current and the sneak-path management. To tackle this challenge, we propose in this paper, a new sense amplifier able to generate an auto-reference taking into account leakage current of unselected cells, including a regulation loop to compensate voltage drop due to reading current sensing. This auto-referenced sense, built on the chargesharing principle, is designed on a 28nm FDSOI technology and validated through extensive Monte-Carlo and corner cases simulations. Layout and postlayout simulation results are also provided. From the simulation results, our sense amplifier is demonstrated to be robust for an ultra-large range of sneak-path current and consequently for a large range of memory array size, suitable for embedded memory in high-end microcontroller.

Mots clés: PCM; OTS; non-volatile memory sensing; sneak-path compensation

Domaines: Informatique [cs]

J Gasquez, B Giraud, P Boivin, Y Moustapha-Rabault, V Della Marca, et al.. A Regulated Sensing Solution based on a Self-Reference Principle for PCM+OTS Memory Array. 29th IFIP/IEEE International Conference on Very Large Scale Integration - System on a Chip (VLSI-SoC), Oct 2021, Singapore, Singapore. pp.225-244. ⟨hal-04419842v2⟩