A new process for the fabrication of planar antenna coupled Ni-NiOx-Ni tunnel junction devices

► Methods to fabricate planar, geometrically asymmetric Ni-NiOx-Ni tunnel diodes are developed. ► Planar structure decreased the parasitic capacitance enabling high cut-off frequency. ► Ni electrodes provided the surface oxidation control and low band edge offset with its native oxide. ► Asymmetric geometry of the electrodes resulted in electrical asymmetry across zero bias. ► Three Ni oxidation methods are studied to build a thin, but durable oxide for the tunnel barrier.