On-chip superconductivity via gallium overdoping of silicon

We report on superconducting properties of gallium-enriched silicon layers in commercial (100) oriented silicon wafers. Ion implantation and subsequent rapid thermal annealing have been applied for realizing gallium precipitation beneath a silicon-dioxide cover layer. Depending on the preparation parameters, we observe a sharp drop to zero resistance at 7 K. The critical-field anisotropy proofs the thin-film character of superconductivity. In addition, out-of-plane critical fields of above 9 T and critical current densities exceeding 2 kA/cm² promote these structures to be possible playgrounds for future microelectronic technology