Molecular beam epitaxial GaAs-AlxGa1-xAs heterostructures for metal semiconductor field effect transistor applications

High-quality GaAs-AlxGa1-xAs heterostructures for metal semiconductor field effect transistor (MESFET) applications have been grown by molecular beam epitaxy. 0.5-μm-thick n-type GaAs active layers with free-carrier concentrations ∼1.1×1017 cm−3 and room-temperature electron mobilities ∼4400 cm2 V−1 sec−1 were routinely obtained on top of undoped AlxGa1-x As (x∼0.4) buffer layers. MESFET’s fabricated on these layers showed approximately 2000-Ω-mm output resistance.