A SUPERCONDUCTING-BASE HOT-ELECTRON TRANSISTOR (SBHET) USING A HIGH-TC SUPERCONDUCTOR

The quantum mechanical reflection (QMR) at the interface between the high-T(c) superconductor base and the semiconductor collector could be reduced to less than a few percent, if electrons are injected at energies close to the collector barrier. Values of f(max) are possible as high as 270 GHz and 400 GHz for SBHET Si and InAs by reducing the contact resistance of the semiconductor to as low as 10-OMEGA-mu-m2. We propose the use of ultra-thin metal films as layers to protect Si surfaces from oxidation and interdiffusion. BiSrCaCuO films on the SI(100) substrate covered with an Ag monolayer are deposited by the MBE method in two stages, the first is 1000 angstrom thick at T(sub) = 530-degrees-C and the next 3000 angstrom thick at T(sub) = 700-degrees-C, which showed the superconductivity, T(c) almost-equal-to 20 K. Interdiffusion between the oxide films and Si substrate was hardly observed by AES depth analysis.