GaAs/AlGaAs Hereojunction Gate Field Effect Transistor.
WESTINGHOUSE RESEARCH AND DEVELOPMENT CENTER PITTSBURGH PA
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An enhancement mode junction field effect transistor JFET using an AlxGal-xAs gate and a GaAs channel was designed and fabricated in an attempt to establish a GaAs logic technology base permitting direct coupling without the necessity for level shifting, while at the same time, permitting a wider dynamic range noise margin due to the larger anticipated built-in voltage of the heterojunction gate. The heterojunction layers were grown by liquid phase epitaxy LPE. Although the control of doping level and morphology was good, the GaAs layers were thicker than necessary, resulting in some depletion mode action by the JFET. The high forward biased gate voltage of these devices, 2-3 volts, was the result of a rectifying contact on the p-type AlxGal-xAs and not due to the anticipated larger work function difference. The devices showed a cut-off frequency, fmax, of 1.5 GHz. Author
- Electrical and Electronic Equipment
- Solid State Physics