Fabrication of air-bridge sub-micron Schottky junctions on Ge/SOI for THz detection

•Schottky diodes on epitaxial germanium grown on SOI substrate were fabricated.•T-Gate technology was implemented on epitaxial germanium.•T-shaped Schottky anode fabricated has footprint width below 400 nm.•Electrical characterization shows a good rectifying behavior.•Ideality factor between 1 and 2 and series resistance between 100 and 250 Ω were found.

We report on the fabrication and electrical characterization of Schottky diodes on epitaxial relaxed germanium for THz detection, which implement both a sub-micron junction area and the air-bridge technology. The small footprint necessary for low capacitances and T-shaped contacts are obtained by using a triple layer of electronic resists with different sensitivity. The cross-sectional analyses revealed a clearly suspended air-bridge and the T-shape of the metal contact with footprint width below 400 nm. The electrical characterization at room temperature shows well defined Schottky diode behavior with ideality factor between 1 and 2 and low series resistance suitable for THz detection.

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