Abstract: A method is disclosed for the selective etching of a multi-layer metal oxide stack comprising a platinum layer on a TiN layer on an HfO2 or ZrO2 layer on a substrate. In some embodiments, the method comprises a physical sputter process to selectively etch the platinum layer, followed by a plasma etch process comprises CHF3 and oxygen to selectively etch the TiN, HfO2 or ZrO2 layers with respect to the substrate.

Abstract: A method is disclosed for the selective etching of a multi-layer metal oxide stack comprising a platinum layer on a TiN layer on an HfO2 or ZrO2 layer on a substrate. In some embodiments, the method comprises a physical sputter process to selectively etch the platinum layer, followed by a plasma etch process comprises CHF3 and oxygen to selectively etch the TiN, HfO2 or ZrO2 layers with respect to the substrate.

Abstract: Provided are methods for etching resistive switching and electrode layers in resistive random access memory (ReRAM) cells. Both types of layers are etched in the same operation. This approach simplifies processing in comparison to conventional etching, in which each layer is etched individually. The composition of etchants and process conditions are specifically selected to provide robust and effective etching of both types of layers. The two etching rates may be comparable and may be substantially the same, in some embodiments. Plasma etching involving tri-fluoro-methane and oxygen containing etchants may be used on electrode materials, such as titanium nitride, platinum, and ruthenium, and on resistive switching materials, such as oxides of transition metals. For example, a combination of titanium nitride and hafnium oxide may be etched using such processes. In some embodiments, an etched stack includes a third layer, which may function as a current limiter in ReRAM cells.