Fabrication, characterization and simulation of resistive switching devices based on high-k dielectrics
Research Partners: 3 (IMB-CNM (CSIC), Universidad de Valladolid, Universidad de Granada)
Funding Agency / Institution: Ministerio de Economia, Industria y Competitividad
Period: 4 years (1/1/2015-31/12/2018)
Project coordinator: Francesca Campabadal (IMB-CNM, CSIC)
Research team members: María Cruz Acero, Mireia Bargalló González, José Calvo, Samuel Poblador, Miguel Zabala, Francesca Campabadal
Total funding: 100.914 €
Resistive switching memories (RRAMs) are the most promising candidates to substitute current Flash memories in the non-volatile memory realm. Thus, the scientific and technological interest on these devices has strongly increased in the last few years. Although resistive switching phenomena have been observed in many metal-oxide-metal or metal-oxide-semiconductor structures, a lot of questions come up in connection with the origin of conduction and resistive-switching mechanisms. Consequently, before the RRAM commercial use, some critical issues need to be addressed. One of the most important is the occurrence of fluctuations in the different resistive states. This effect induces device-to-device and cycle-to-cycle variability. This variability affects parameters such as the set and reset voltages or current levels. Understanding the switching variability and its influence on the complete circuit performance is essential to foster RRAM-based industrial applications. The device endurance is also another key point. In answering these questions we will step forward to the fundamental facets RRAM study: fabrication, characterization, simulation and compact modelling; all the knowledge to be developed on these topics will be necessary in the way to go from laboratory prototypes to commercial applications.
Taking all of this into consideration, our proposal is focused on gaining a deeper insight into the technology and physics of RRAMs: different materials and device structures, variability, endurance and other critical concerns on the device performance. To do so we have put together the resources of three research groups (IMB-CNM, Universidad de Valladolid and Universidad de Granada) in order to cover a broad spectrum of research issues related to RRAMs. We will cover the fabrication, using our facilities and those of our partners, characterization and also device simulation and modelling oriented to circuit simulation, both considering the digital (memory) and analog (memristor) viewpoints. By using the latter devices, we will be able to analyze new circuit design paradigms such as bioinspired and neuromorphic applications.
In this context, we will take advantage of our synergies for this project proposal: a group whose expertise in fabrication and characterization of high-k dielectrics and RRAM devices has been widely proved (IMB); a group with a vast experience in electrical characterization techniques (UVa) along the last twenty years; and a group with knowledge in physical simulation and compact modelling (including also ad hoc circuit applications) of different types of electron devices (UGR).
We will get through the study described above by means of the following objectives:
1. Development of process technologies for the fabrication of MIS and MIM structures as RRAM cells based on high-k dielectrics.
2. Study of the electrical characteristics and resistive switching mechanisms of MIS and MIM structures and their dependence on device processing, materials, and dimensions.
3. Analysis of the switching variability and reliability in RRAM cells.
4. Study of the radiation effects on the high-k layers and its impact on resistive switching.
5. Development of RRAM simulation tools.
6. RRAM and Memristor compact modelling.
M. M. Mallol, M.B. Gonzalez, F. Campabadal. Impact of the HfO2/Al2O3 Stacking Order on Unipolar RRAM Devices. Microelectron. Eng., vol. 178, pp. 168-172 (2017).
M. Pedro, J. Martin-Martinez, M. B. Gonzalez, R. Rodriguez, F. Campabadal, M. Nafria, X. Aymerich. Tuning the Conductivity of Resistive Switching Devices for Electronic Synapses. Microelectron. Eng., vol. 178, pp. 89-92 (2017).
D. Arumí, M.B. Gonzalez, F. Campabadal. RRAM Serial Configuration for the Generation of Random Bits. Microelectron Eng., vol. 178, pp. 76-79 (2017).
S. Dueñas, H. Castán, H. García, E.Miranda, M.B. Gonzalez, F. Campabadal. Study of the admittance hysteresis cycles in TiN/Ti/HfO2/W-based RRAM devices. Microelectron. Eng., vol. 178, pp. 30-33 (2017).
G. González-Cordero, M.B. González, H. García, F. Campabadal, S. Dueñas, H. Castán, F. Jiménez-Molinos, J.B. Roldán. A physically based model for resistive memories including a detailed temperature and variability description. Microelectron. Eng., vol. 178, pp. 26-29 (2017).
Gerardo González-Cordero, Francisco Jiménez-Molinos, Juan Bautista Roldán, Mireia Bargalló González, and Francesca Campabadal. In-depth study of the physics behind resistive switching in TiN/Ti/HfO2/W structures. J. Vac. Sci. Technol. B, vol. 35, No. 1, pp. 01A110 (2017).
A. Rodriguez-Fernandez, J. Suñé, E. Miranda, M.B. Gonzalez, and F. Campabadal. Function-fit model for the rate of conducting filament generation in constant voltage stressed multilayer oxide stacks. J. Vac. Sci. Technol. B, vol. 35, No. 1, pp. 01A108 (2017).
Mireia Bargallo Gonzalez, Javier Martin-Martinez, Marcos Maestro, María Cruz Acero, Montserrat Nafría, and Francesca Campabadal, Investigation of Filamentary Current Fluctuations Features in the High-Resistance State of Ni/HfO2-Based RRAM. IEEE Trans. Electron Devices, vol. 63, No. 8, pp. 3116-3121 (2016).
César Vaca, Mireia B. González, Helena Castán, Héctor García, Salvador Dueñas, Francesca Campabadal, Enrique Miranda, and Luis A. Bailón, Study From Cryogenic to High Temperatures of the High- and Low-Resistance-State Currents of ReRAM Ni–HfO2–Si Capacitors. IEEE Trans. Electron Devices, vol. 63, No. 5, pp. 1877-1883 (2016).
M.A. Villena, J.B. Roldán, M.B. González, P. González-Rodelas, F. Jiménez-Molinos, F. Campabadal, and D. Barrera. A new parameter to characterize the charge transport regime in Ni/HfO2/Si-n+-based RRAMs. Solid-State Electron., vol. 118, pp. 56-60 (2016).