MESFET

MESFETs are constructed in compound semiconductor technologies lacking high quality surface passivation, such as gallium arsenide, indium phosphide, or silicon carbide, and are faster but more expensive than silicon-based JFETs or MOSFETs.

The first MESFETs were developed in 1966, and a year later their extremely high frequency RF microwave performance was demonstrated.

[citation needed] While this restriction inhibits certain circuit possibilities as the gate must remain reverse-biased and cannot, therefore, exceed a certain voltage of forward bias, MESFETs analog and digital devices work reasonably well if kept within the confines of design limits.

As a result, most production MESFETs use a built-up top layer of low-resistance metal on the gate, often producing a mushroom-like profile in cross-section.

[citation needed] Numerous MESFET fabrication possibilities have been explored for a wide variety of semiconductor systems.