  It is well known that conventional Field Effect Transistors (FET's) require a
change in the channel potential of at least 60 mV at 300K to effect a change in
the current by a factor of ten, and this minimum subthreshold slope S puts a
lower limit of fundamental nature on the operating voltage and hence the power
dissipation in standard FET based switches. Here we show that by replacing the
standard insulator with a ferroelectric insulator of the right thickness it
should be possible to implement a step-up voltage transformer that will amplify
the gate voltage thus leading to values of S lower than 60 mV/decade and
enabling low voltage/low power operation. The voltage transformer action can be
understood intuitively as the result of an effective negative capacitance
provided by the ferroelectric capacitor which arises from an internal positive
feedback that in principle could be obtained from other microscopic mechanisms
as well. Unlike other proposals to reduce S this involves no change in the
basic physics of the FET and thus does not affect its current drive or impose
other restrictions.
