This work studies the self-heating (SH) effect in ultra-thin body ultra-thin buried oxide (UTBB) FDSOI MOSFETs at cryogenic temperatures down to 77 K. S-parameter measurements in a wide frequency range. with the so-called RF technique. are employed to assess SH parameters and related variation of analog figures of merit (FoMs) at different temperatures. https://www.knowall.blog/