[paper] FD-SOI CMOS RF FoM

28-nm FD-SOI CMOS RF Figures of Merit Down to 4.2 K

Lucas Nyssens¹ (Graduate Student Member, IEEE), Arka Halder¹, Babak Kazemi Esfeh¹,
Nicolas Planes², Denis Flandre¹ (Senior Member, IEEE), Valeriya Kilchytska¹
and Jean-Pierre Raskin¹ (Fellow, IEEE)
IEEE J-EDS, vol. 8, pp. 646-654, 2020,
DOI: 10.1109/JEDS.2020.3002201

¹UCL, 1348 Louvain-la-Neuve (B) ²ST-Microelectronics, 38920 Crolles (F)

Abstract: This work presents a detailed RF characterization of 28nm FD-SOI nMOSFETs at cryogenic temperatures down to 4.2K. Two main RF Figures of Merit (FoMs), i.e., current-gain cutoff frequency (f_T) and maximum oscillation frequency (f_max), as well as parasitic elements of the small-signal equivalent circuit, are extracted from the measured S-parameters. An improvement of up to ∼130GHz in f_T and ∼75GHz in f_max is observed for the shortest device (25nm) at low temperature. The behavior of RF FoMs versus temperature is discussed in terms of small-signal equivalent circuit elements, both intrinsic and extrinsic (parasitics). This study suggests 28nm FD-SOI nMOSFETs as a good candidate for future cryogenic applications down to 4.2K and clarifies the origin and limitations of the performance.

FIG: Small-signal equivalent circuit of the RF MOSFETs

Aknowledgement: This work was supported in part by Eniac “Places2Be” and in part by Ecsel “Waytogofast” Projects. The work of Lucas Nyssens was supported by the Fonds de la Recherche Scientifique - FNRS. This paper is based on a paper entitled “28 FDSOI RF Figures of Merit Down to 4.2 K,” presented at the 2019 IEEE S3S Conference.