Sub-threshold electron mobility in SOI MESFET

Micropower circuits use subthreshold MOSFETs that consume minimal power resulting from the combination of ultra-low drain currents (10^-11 < I_d < 10^-5 A/μm) and small drain voltages required for saturation (V_d^sat ∼150-200mV). Unfortunately, sub-threshold CMOS is a slow technology, with micropower circuits limited to operating frequencies below ∼1 MHz. To achieve higher sub-threshold operating frequencies, we have proposed a Schottky Junction Transistor (SJT) as an alternative to sub-threshold MOSFET devices. It adopts a MESFET architecture and exhibits higher electron mobility. The enhanced MESFET mobility leads to a corresponding increase in the cut-off frequency f _T compared to a similar gate length MOSFET carrying the same amount of current.