Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 40: Resistive switching II (jointly with DF, KR, HL)
DS 40.1: Vortrag
Freitag, 30. März 2012, 11:00–11:15, H 0111
Resistive switching mechanism of Ti/HfO2/TiN RRAM cells studied by nondestructive hard x-ray photoelectron spectroscopy — •Małgorzata Sowińska1, Thomas Bertaud1, Damian Walczyk1, Christian Walczyk1, Sebastian Thiess2, Wolfgang Drube2, and Thomas Schroeder1 — 1IHP, Im Technologiepark 25, 15236 Frankfurt/Oder, Germany — 2DESY, Notkestrasse 85, 22607 Hamburg, Germany
A variety of different metal-insulator-metal (MIM) multilayered structures reveal reversible changes in resistance upon applying bias voltages across the layers. The physical mechanism of this resistive switching effect in such MIM cells is mostly unknown up to nowadays, although different models depending on the switching behaviour (unipolar or bipolar) and the conducting path type (filamentary or interface) have been proposed. In order to identify whether the resistance variation in the Ti/HfO2/TiN system is related to local changes in the chemistry or to charge distribution we performed ex-situ and in-situ hard x-ray photoelectron spectroscopy (HAXPES) studies. This technique is well suited for investigating the buried interface of our resistive random access memory (RRAM) cell in a nondestructive way. In result, spectral differences observed between as-deposited and electrically switched devices lead us to the conclusion that the Ti/HfO2 interface was modified, which can be associated with an interface-type model. Furthermore, we have also better revealed the impact of the current compliance on the HAXPES spectra of our device.