Transistor action in novel GaAs/W/GaAs structures

Structures containing thin polycrystalline layers of W embedded in essentially single crystal GaAs have been grown by molecular beam epitaxy. The W layers exhibit resistivities of 90–300 μΩ cm and Schottky barriers to both substrate and overgrown GaAs. The structures can act as metal gate transistors with β of 0.2–1.4 and α of 0.4–0.6. These are the first reported metal gate transistors in the III-V materials and the first using a nonepitaxial base and laterally seeded overgrowth. The use of a nonepitaxial base represents a degree of freedom which may be usefully exploited in a wide class of materials systems and may be important for the development of future metal gate transistors, especially in III-V materials.