MESFET structure

C4.1 General remarks on GaN-based transistors and potential for high temperature/power operation C4.2 GaN FET structures MESFET, MISFET, JFET and MODFET... 

FIGURE 1 (a) A Si-doped GaN MESFET [2] (reproduced by permission of the Electrochemical Society Inc.), (b) A MISFET with Si3N4 dielectric insulator [2] (reproduced by permission of the Electrochemical Society Inc.), (c) A GaN JFE p- and n-types are formed by 40Ca and Si implantation, respectively (reproduced by permission of the authors) [4], (d) A typical group Ill-nitride MODFET layer structure. 

Different types of SiC Field Effect Transistors, Metal Oxide Semiconductor Transistors (MOSFETs), Metal Semiconductor Field Effect Transistors (MESFETs), and Junction Field Effect Transistors (JFETs) compete for future applications in high temperature and harsh environment electronics. This Datareview details these various types of FETs, the structures used and the performances obtained. Interesting recent developments and potential applications, such as FET integrated circuits, a hybrid operational amplifier and an inverter circuit are also outlined. 

Transistors of diamond have been investigated mainly with the p-channel MBS type and p-channel MOS type, because the only reproducible channels are available for B-doped p-type diamond. However, from a historical viewpoint, research activities on MESFETs and MOSFETs were preceded by several pioneering studies with other device structures. 

If the half-width a of the MESFET channel is designed to be larger than the zero bias depletion width of the MESFET gate structure, the MESFET behaves as a depletion-mode (or normally on) device structure. When an increasing positive bias is applied to the drain (Db) of the Baliga pair with gate (Gb) shorted to the source (Sb), the voltage is initially supported by... 

By using this relationship, Vg can be obtained from Vg and substituted into the equations derived for a MESFET to obtain the solutions for MOSFET structures involving an insulator under the gate. 

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