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MESFET

Subtopic

Metal  Semiconductor Field Effect Transistor

•They use metal semiconductor schottky junction for the gate contact & hence the name is MESFET.

•Unipolar Microwave transistors have several advantages as used as replacement of bipolar transistors in radar application.

•They have higher efficiency, max input impedance and lower noise figures.

•JFET & IGFET are also suitable for microwave amplification and oscillation.

•GaAs MESFET due to their higher mobility (6 times larger than Si),

•smaller parasitic resistances, larger transconductances &  smaller transit time are always preferred.

•The ohmic contacts for source &drain are made on the top of epitaxial layer using Au-Ge, AU-Te or Au-Te-GE alloys.

•In between another contact made up of metal Al semiconductor schottky junction is added called gate.

nMESFET = Metal Semiconductor Field Effect Transistor = Schottky gate FET.

nThe MESFET consists of a conducting channel positioned between a source and drain contact region.

nThe carrier flow from source to drain is controlled by a Schottky metal gate.

nThe control of the channel is obtained by varying the depletion layer width underneath the metal contact which modulates the thickness of the conducting channel and thereby the current.

References

  • WikiNote Foundation
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Created by Sujit Wagh on 2017/10/26 17:38