Static characteristics of gate-all-around SOI MOSFETs at cryogenic temperatures

The operation of so-called gate-all-around (GAA) dual-gate silicon-on-insulator (SOI) MOSFETs at cryogenic temperatures (77 K and 4.2 K) is discussed. It is shown that the transconductance increases by a factor of two upon cooling to 77 K, both for the subthreshold edge conduction and for the inversion channel. Therefore, the performance improvement of the GAA structures over conventional SOI, or bulk MOSFETs is maintained down to liquid helium temperatures. Furthermore, the n-channel devices show negligible hysteresis and kink even at 4.2 K. Metastable behaviour is only observed after the application of a proper bias step to the back-gate electrode.