Implantation, damage, and regrowth of high Tc superconductors
Abstract We have observed superconductivity in thin films of (La1−xSrx)2CuOy which are fabricated by implanting evaporated La/Cu multilayer films with Sr and annealing in oxygen. The films are insulating and partially transparent as-implanted, but they darken and become conducting at annealing temperatures as low as 500°C. The resistive behavior is very sensitive to the annealing conditions and the superconducting layer appears to be buried beneath the surface. Similarly, implantation of F, O, and Ne into single crystals and high quality (χmin
Reproducible technique for fabrication of thin films of high transition temperature superconductors
We report on a new process to make films of Y1Ba2Cu3O7 using coevaporation of Y, Cu, and BaF2 on SrTiO3 substrates. The films have high transition temperatures (up to 91 K for a full resistive transition), high critical current densities (106 A/cm2 at 81 K), and a reduced sensitivity to fabrication and environmental conditions. Because of the lower reactivity of the films, we have been able to pattern them in both the pre‐annealed and post‐annealed states using conventional positive photoresist technology.
Electrical Transport in thin Silicide Films
This paper reviews our recent studies of electrical transport in thin suicide films. Resistivity as a function of temperature, Hall effect, and magnetoresistance have been characterized for CoSi 2 and NiSi 2 and in conjunction with band theory provide estimates of important electronic parameters, viz . carrier densities and carrier scattering lengths. Resistivity data for TiSi 2 and TaSi 2 are included. Also examined in resistivity are (i) effects produced by ion bombardment which show CoSi 2 to have an unusual susceptibility to radiation damage and (ii) classical size effects in the very thin film regime which show the boundary scattering to be principally specular. As an application we describe a Si/CoSi 2 /Si heterostructure transistor recently developed.