GaAs MESFET and HEMT

 

GaAs processes are recognized by their high speed operation for digital and analog circuits. They have also been used in opto-electronic devices. GaAs processes suffer from several problems

• Maturity of technology: The processes are not mature. It was only recently that GaAs processes could achieve high integration (in the order one million transistors).
• Analog design: Analog circuit design has been affected by the schuttky diode at the gate. This diode is in a forward bias direction. For an enhancement mode MESFET this leaves a gate-source voltage range of 0.1 V to 0.6 V.
• Price and availability: GaAs processes are generally expensive and not easily accessible.
• Opto-electronic devices are only available in very specialized processes.