Epitaxial, Silicon-Compatible CoSi₂ Thin Film SQUID with Constriction-Type Junction

Transition metal silicides are widely used in integrated circuits as contacts and interconnect. ${CoSi_2}$ has superconducting ${T_c}$ of 1.4 K and lattice mismatch to Si of 1.2%, thus making it promising for integrating silicon technology into superconducting device fabrication. Here we demonstrate the growth of epitaxial ${CoSi_2}$ thin film on Si(111) substrate and the fabrication of a constriction-type superconducting quantum interference device (SQUID) by silicidation of Co metal on the silicon substrate. The ${CoSi_2}$ -Si interface shows ${CoSi_2} \ (111)$ // Si(111) epitaxy, with in-plane texture ${CoSi_2} \ (100)$ // Si(111) and ${CoSi_2 \ (110)}$ // Si(111). The fabricated SQUID has a superconducting loop area of 0.8 μm2, the oscillating critical current with the applied magnetic field typical for SQUID is observed with ${φ_0}$ = 1.3 mT. The junction resistance of constriction-type SQUID is calculated to be linear with device channel length.