Superconducting Layers by Gallium Implantation and Short-Term Annealing in Semiconductors

Superconducting layers in silicon and germanium are fabricated via gallium implantation through a thin $SiO_2$ cover layer and subsequent rapid thermal annealing. Gallium accumulation at the $SiO_2//Si$ and $SiO_2//Ge$ interfaces is observed but no pure gallium phases were found. In both cases superconducting transition occurs around 6-7 K which can be attributed to the metallic conducting, gallium rich interface layer. However, the superconducting as well as the normal-state transport properties in gallium overdoped silicon or germanium are different.