DIFFERENT CHARACTERISTICS OF METAL (COSI2) INSULATOR (CAF2) RESONANT-TUNNELING TRANSISTORS DEPENDING ON BASE QUANTUM-WELL LAYER

The transistor action with negative differential resistance (NDR) of a nanometer-thick metal (CoSi2)/insulator (CaF2) resonant tunneling tra nsistor is discussed for two transistor structures. These transistors are composed of metal-insulator (M-I) heterostructures with two metall ic (CoSi2) quantum wells and three insulator (CaF2) barriers grown on an n-Si (111) substrate. One of the two structures has the base termin al connected to one of the quantum wells next to the collector, and th e other, to one next to the emitter. Although base resistance is high maybe due to the damage caused during the fabrication process, the two transistors show different characteristics, as expected theoretically . Transfer efficiency alpha (= I(C)/I(E)) close to unity was obtained at 77 K for electrons through the resonant levels in M-I heterostructu res.