GaN FET Structures MESFET, MISFET, JFET and MODFET

TABLE 1 Various types of group Ul-nitride FETs. 

Device MESFET MISFET/HIGFET JFET MODFET/HFET 

Gate formation Schottky gate on GaN channel Metal gate on dielectric insulator (such as Si3N4, AIN) Ohmic contact to p-GaN gate Schottky gate on AlGaN barrier 

Disadvantages Low electron velocity, low current Extra gate bias required to compensate piezoelectric field due to inverted structure Low electron velocity, low current, difficulty in forming a short gate Complex layer in growth 

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. 

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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... 

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