Resistance switching of copper-doped tantalum oxide prepared by oxidation of copper-doped tantalum nitride

A thin copper-doped tantalum oxide (Cu-TaOx) film was prepared by plasma oxidation of a copper-doped tantalum nitride (Cu-TaN) and its resistance switching behavior was studied. A Cu-TaN film was firstly deposited by co-sputtering of copper and tantalum in a gas mixture of argon and nitrogen as the bottom electrode for a resistance switching device. Subsequently, the Cu-TaN film was oxidized in an oxygen-containing plasma to form an insulating layer. Then a TaN film was deposited on top of the insulating layer as the top electrode to form a MIM structure. The TaN/Cu-TaOx/Cu-TaN (MIM) device exhibited bipolar resistance switching when DC voltages were swept. The MIM device was switched from a high resistive state (HRS) to a low resistive state (LRS) at a SET voltage between +0.65 and +0.85 V, and were switched from LRS to HRS at a RESET voltage between -0.4 and -0.5 V when a compliant current of 3.5 mu A was utilized. The SET voltage was between +0.7 and +1.15 V and the RESET voltage was around -0.6 V when a compliant current was set to 13 mu A. The resistance ratios of R-HRS/R-LRS measured at +0.3 V were above 10 and 100 when compliant currents of 3.5 and 13 mu A were utilized, respectively. The resistance switch was possibly attributed to the reaction in composite filamentary paths which were formed inside the Cu-TaOx layer. (C) 2012 Elsevier B.V. All rights reserved.