Perspectives of UTBB FD SOI MOSFETs for Analog and RF Applications

Ultra-thin body and buried oxide (UTBB) fully depleted (FD) silicon-on-insulator (SOI) MOSFETs are widely recognized as a promising candidate for 20 nm technology node and beyond, due to outstanding electrostatic control of short channel effects (SCE). Introduction of a highly-doped layer underneath thin buried oxide (BOX), so called ground-plane (GP), targets suppression of detrimental parasitic substrate coupling and opens multi-threshold voltage (V Th ) and dynamic-V Th opportunities within the same process as well as the use of back-gate control schemes [1, 2]. Electrostatics, scalability and variability issues in UTBB MOSFETs as well as their perspectives for low power digital applications are widely discussed in the literature [1–5]. At the same time assessment of UTBB FD SOI for analog and RF applications received less attention. This chapter will discuss Figures of Merit (FoM) of UTBB MOSFETs of interest for further analog/RF applications summarizing our original research over the last years [6–15]. Device analog/RF performance is assessed through the key parameters such as the transconductance, g m , the output conductance, g d , the intrinsic gain, A v and the cut-off frequencies, f T and f max. Particular attention is paid to (1) a wide-frequency band assessment, the only approach that allows fair performance prediction for analog/RF applications; (2) the effect of parasitic elements, whose impact on the device performance increases enormously in deeply downscaled devices, in which they can even dominate device performance. Whenever possible, we will compare FoM achievable in UTBB FD SOI devices with those reported for other advanced devices