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

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.