The evolution of wide-bandgap semiconductor transistor technology is placed in historical context with other
active device technologies. The relative rapidity of GaN transistor development is noted and is attributed to
the great parallel activity in the lighting sector and the historical experience and business model from the III-V
compound semiconductor sector. The physical performance expectations for wide-bandgap technologies such
as Gallium-Nitride Field-Effect Transistors (GaN FETs) are reviewed. We present some device characteristics.
Challenges met in characterising, and prospects for modeling GaN FETs are described. Reliability is identified
as the final remaining hurdle facing would-be foundries. Evolutionary and unsurprising applications as well as
novel and revolutionary applications are suggested. Novel applications include wholly monolithic switchmode
power supplies, simplified tools for ablation and diathermy in tissue, and very wide dynamic range circuits for
audio or low phase noise signal generation. We conclude that now is the time to embark on circuit design of MMICs in wide-bandgap technology. The potential for fabless design groups to capitalise upon design IP without strong geopraphic advantage is noted.