| AVS 66th International Symposium & Exhibition | |
| Thin Films Division | Wednesday Sessions |
| Session TF+EM-WeA |
| Session: | Emerging Thin Film Materials: Ultra-wide Bandgap and Phase Change Materials |
| Presenter: | Guillaume Bourgeois, CEA-LETI, France |
| Authors: | G. Bourgeois, CEA-LETI, France G. Navarro, CEA-LETI, France M.C. Cyrille, CEA-LETI, France J. Garrione, CEA-LETI, France C. Sabbione, CEA-LETI, France M. Bernard, CEA-LETI, France E. Nolot, CEA-LETI, France E. Nowak, CEA-LETI, France |
| Correspondent: | Click to Email |
Phase-Change Memory (PCM) is today the most mature among innovative back-end non-volatile memory technologies, thanks to a wide set of interesting features making PCM technology enough versatile to meet different applications’ requirements [1]. A PCM device experiences a physical change of a chalcogenide material sandwiched between two electrodes made possible by the current induced Joule heating flowing through the cell. To achieve the amorphous phase, the PCM in the crystalline phase has to be melted, then rapidly quenched (RESET operation). Thanks to the switching phenomenon, the material in the amorphous phase changes abruptly its conductivity starting to be highly conductive, and can recover the crystalline phase thanks to a specific thermal profile during the pulse application, that provides the energy necessary to the atomic reorganization (SET operation). Thereby, PCM thermal stability relies on the magnitude of the activation energy of the crystallization that results from the combination of crystals nucleation and growth phenomena, on which also the device programming speed relies. Thus, a general trade‑off exists between the time required for the SET operation and the device data retention performance [2] (Figure 1). Sb-rich GeSbTe compounds are suitable for high-speed performances with a programming time down to tens of ns still ensuring high endurance and scalability, promising for Storage Class Memory applications (SCM) [3]. Reliability at high temperature is the main requirement to target automotive embedded applications. Ge-rich compositions revealed an endurance of 107 cycles up to 175 °C and high temperature data retention compatible with embedded standards. We present here the device performance tuning thanks to the phase‑change material stoichiometry engineering (Figure 2). Moreover, we highlight the possibility to boost the PCM performances, such as SET speed and Multi Level Cell capability, thanks to dedicated programming strategies [4].
REFERENCES
[1] F. Arnaud et al, “Truly Innovative 28nm FDSOI Technology”, IEDM 2018.
[2] G. Navarro et al, “Non-Volatile Resistive Memory”, ECS 2016.
[3] V. Sousa et al, “Phase Change Memory”, Chapter 7, Springer 2018.
[4] J. Kluge et al, “High Operating Temperature Reliability”, IMW 2016.