Germanium has always been an interesting material for use in semiconductors because it conducted well (superior hole mobility). Trouble is, germanium’s low band-gap energy of 0.66 eV has meant the material suffers from a lot of reverse junction current leakage. This gives it a reputation for high static power dissipation. Recently, a group of German scientists came up with a way to overcome the reverse leakage problem.
Their work applies to the off-state leakage in germanium nanowire Schottky barrier transistors. Writing in the journal ACS Nano, the 13 researchers say they use a device layout with two independent gates to induce an additional energy barrier to a channel that blocks the undesired carrier type. Interestingly, they say the polarity of the same doping-free device can be dynamically switched between p- and n-type.
Their germanium nanowire approach isn’t the first polarity-controllable device concept, but the researchers say it outperforms other ideas in terms of threshold voltages and normalized on-currents. Moreover, they say the leakage current suppression and polarity control can also work at highly scaled geometries, so it holds promise for future energy-efficient systems.
Leave a Reply