title: Geometric conductive filament confinement by nanotips for resistive switching of HfO2-RRAM devices with high performance.
abstract: Filament-type HfO2-based RRAM has been considered as one of the most promising candidates for future non-volatile memories. Further improvement of the stability, particularly at the "OFF" state, of such devices is mainly hindered by resistance variation induced by the uncontrolled oxygen vacancies distribution and filament growth in HfO2 films. We report highly stable endurance of TiN/Ti/HfO2/Si-tip RRAM devices using a CMOS compatible nanotip method. Simulations indicate that the nanotip bottom electrode provides a local confinement for the electrical field and ionic current density; thus a nano-confinement for the oxygen vacancy distribution and nano-filament location is created by this approach. Conductive atomic force microscopy measurements confirm that the filaments form only on the nanotip region. Resistance switching by using pulses shows highly stable endurance for both ON and OFF modes, thanks to the geometric confinement of the conductive path and filament only above the nanotip. This nano-engineering approach opens a new pathway to realize forming-free RRAM devices with improved stability and reliability.
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.|Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education &International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Niu
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors.forename: Pauline
authors.initials: P
authors.lastname: Calka
authors.affiliation: Dept. Electronics Engineering University of Rome, "Tor Vergata" via del Politecnico 1, 00133 Roma, Italy.
authors.forename: Matthias
authors.initials: M
authors.lastname: Auf der Maur
authors.affiliation: Dept. Electronics Engineering University of Rome, "Tor Vergata" via del Politecnico 1, 00133 Roma, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Santoni
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors.forename: Subhajit
authors.initials: S
authors.lastname: Guha
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors.forename: Mirko
authors.initials: M
authors.lastname: Fraschke
authors.affiliation: Institut des Nanotechnologies de Lyon (INL), UMR CNRS 5270, INSA de Lyon, 7 Avenue Jean Capelle, 69621 Villeurbanne, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Hamoumou
authors.affiliation: Institut des Nanotechnologies de Lyon (INL), UMR CNRS 5270, INSA de Lyon, 7 Avenue Jean Capelle, 69621 Villeurbanne, France.
authors.forename: Brice
authors.initials: B
authors.lastname: Gautier
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Perez
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Walczyk
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wenger
authors.affiliation: Dept. Electronics Engineering University of Rome, "Tor Vergata" via del Politecnico 1, 00133 Roma, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Di Carlo
authors.affiliation: Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
authors.forename: Lambert
authors.initials: L
authors.lastname: Alff
authors.affiliation: IHP GmbH - Leibniz institute for innovative microelectronics, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.|Brandenburgische Technische Universität, Konrad-Zuse Strasse 1, 03046 Cottbus, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schroeder