Improvement of Memristive Characteristic of In-Ga-Zn-O Thin-Film Memristor by Conductive Buffer Layers

A memristive characteristic of an In-Ga-Zn-O (IGZO) thin-film memristor (TFM) has been improved by conductive buffer layers. The IGZO TFM is actually fabricated by inserting the conductive buffer layers between the conductance change film and electrode films, which is made by the difference in the flow rates of the sputtering gas. The device structure is quite simple, namely, the IGZO film is sandwiched between the top and bottom electrodes, and the change in the flow rate is acquired simply by regulating the gas valve. The switching ratio has been improved significantly, because the top and bottom conductive buffer layers act as pseudo-electrode films and hide the Schottky barrier and unfavorable influences, such as current decrease due to the formation of metal-oxide insulator and so on. The candidate constituents for the current path are determined to be H
^-
, and it is suggested that multiple conductive filaments are generated. The proposed method is expected to be effective to improve the memristive characteristics also for various kinds of TFMs.