MESFET Technology

MESFET Technology

MESFET stands for MEtal Semiconductor Field Effect Transistor. It is quite similar to a JFET in construction and terminology. The difference is that instead of using a p-n junction for a gate, a Schottky (metal-semiconductor) junction is used. Here the GaAs substrate is placed in place of Silicon substrate.The short minority-carrier life time and the lack of high-quality insulating films have prevented the development of bipolar devices and delayed MOS technology using GaAs.Thus, the emphasis of GaAs IC technology is in the MESFET area, in which the main concerns are majority carriers transport and metal-semiconductor contact. GaAs has three inherent advantages compared with silicon: higher electron mobility, which results in lower series resistance for a given device geometry.Higher drift velocity at a given electric field, which improves device speed; Ability to made semi-insulating, which can provide a lattice-matched dielectric insulated substrate.It has crystal defects that are many orders of magnitude higher than that of silicon.Si is highly abundant in the Earth's crust, in the form of silicate minerals. The economy of scale available to the silicon industry has also reduced the adoption of GaAs. The gate region of MOSFET is made up of MOS structure and hence it draws very little current in the static conditions. The gate region in MESFET is a metal-semiconductor rectifying contact ,the gate leakage is not negligible.is Because they lack a fast CMOS structure, GaAs logic circuits have much higher power consumption. GaAs does not form a stable adherent insulating layer. a metal-semiconductor rectifying contact ,the gate leakage is not negligible.Because they lack a fast CMOS structure, GaAs logic circuits have much higher power consumption.GaAs does not form a stable adherent insulating layer.