| AVS 62nd International Symposium & Exhibition | |
| Electronic Materials and Processing | Wednesday Sessions |
| Session EM-WeM |
| Session: | Beyond CMOS: Resistive Switching Devices |
| Presenter: | Christophe Vallee, LTM, Univ. Grenoble Alpes, CEA-LETI, France |
| Authors: | C. Vallee, LTM, Univ. Grenoble Alpes, CEA-LETI, France P. Gonon, LTM, Univ. Grenoble Alpes, CEA-LETI, France C. Mannequin, LTM, Univ. Grenoble Alpes, CEA-LETI, France T. Wakrim, LTM, Univ. Grenoble Alpes, CEA-LETI, France M. Saadi, LTM, Univ. Grenoble Alpes, CEA-LETI, France A. Sylvestre, G2elab, Univ. Grenoble Alpes, France |
| Correspondent: | Click to Email |
This work addresses a new class of electrical devices that could be named “memory impedance”, or “MEM-Z” devices. These structures are based on the capability of HfO2 MIM (Metal – Insulator –Metal) to switch both their resistance and capacitance with a memory effect. Recently, during works led on HfO2 OxRAM [1], we found that for a specific design, upon voltage biasing, not only does the resistance changes but the capacitance also varies from positive to negative values. In other words, both the real and imaginary part of the impedance can be controlled by the voltage bias. If the impedance state can be non-volatile (memory function), then a new class of devices (MEM-Z) can be defined. MEM-Z devices (mem-capacitors and mem-inductors) were recently theorized and their potential applications reviewed [2]: like memristors, they can be used as non-volatile memories, for fuzzy logic (non-binary computing based on continuous variables), and as self-learning devices (neuro-inspired systems, adaptive filters…). They can also be used in tunable electronic circuits such as reconfigurable impedance matching network, reconfigurable amplifiers, programmable filters and oscillators.
In the present work we investigate both resistance and capacitance switching of HfO2-based MIM device. By comparison to HfO2 OxRAM, the device has been modified in order to avoid any breakdown during the capacitance switch. Therefore a bi-layer structure is used to obtain a self-compliance MEM-Z device. With this structure a bipolar capacitance cycle has been obtained with decreasing values of capacitance in the ON state. Negative values of capacitance near SET and RESET voltages are also observed. Memory effect for both positive and negative values of capacitance is also demonstrated. At present, the physical origin of capacitance variation is an open question. One hypothesis is that conduction paths, which lead to resistance switching, are the same which lead to capacitance decrease (through the inductive behavior of conduction paths, hopping conduction). This will be discussed in this presentation from the frequency dependence study of the capacitance switch.
[1] P. Gonon, M. Mougenot, C. Vallée, C. Jorel, V. Jousseaume, H. Grampeix, F. El Kamel, "Resistance switching in HfO2 metal-insulator-metal devices", Journal of Applied Physics, vol.107, p.074507 (2010)
[2] Y.V. Pershin, M. Di Ventra, "Memory effects in complex materials and nanoscale systems", Advances in Physics, vol. 60, p.145 (2011)