Current-induced resistivity switching in VO₂ micro-electronic oscillators

Functional metal oxides are a class of emerging materials with novel applications in tunable and reconfigurable microelectronics beyond the CMOS technology. Vanadium dioxide (VO₂) is one such material that is attracting considerable attention for its reversible insulator-to-metal phase transition (IMT). Under electrically controlled IMT process VO₂ devices exhibit electrical switching and negative differential resistance (NDR). Such attributes make VO₂ the ideal candidate for designing tunable micro oscillators for emerging applications such as neuro-morphic computing. We designed, fabricated, and characterized planar VO₂ micro-channel devices with different dimensions. The intrinsic parasitic capacitance of the fabricated devices allowed for stable spontaneous electrical oscillations under current actuation. Our novel approach for controlling the current in the NDR region eliminates the need of an external pulsed power source or external passive components to generate self-sustained electrical oscillations. Such reduction in circuitry complexity is significant for prospective large scale on-chip integration of micro- or nano- oscillators that simplifies the power source design and the connection between oscillators and metal interconnects carrying power to the oscillators.