Patterning of epitaxial VO₂ microstructures by a hightemperature lift-off process

The growing field of oxide-electronics demands adequate fabrication methods that do not impair the material's beneficial properties. To this end, we present a modified lift-off lithography method replacing the conventional polymer mask with an AlO_x based mask. It can sustain the high-temperature and reactive gasses conditions commonly needed for oxide deposition, and is effectively wet-etched in dilute NaOH solutions. Here we demonstrate patterning of VO₂ films. With its metal-insulator transition (MIT) near room temperature, it is attractive for various applications including sensors and transistors. But patterning is challenging since its properties are very sensitive to fabrication processes. We demonstrate patterning of 3 μm wide VO₂ electrodes and show they preserve the MIT magnitude and epitaxial growth of the non-patterned films. Some thinning of the VO₂ is also observed. This process can be useful for patterning other materials that require harsh deposition conditions, and are resilient to low NaOH concentrations.