As-Grown Deposition of Superconducting MgB2 Thin Films by Multiple-Target Sputtering System

As-grown superconducting MgB2 thin films were prepared using a multiple-target sputtering system. The targets were pure B and Mg metal. The MgB2 thin films were deposited at substrate temperatures (Ts) ranging from 207°C to 268°C on Al2O3 (1102) substrates. We found that the critical temperatures (Tc) of the films were increased with increase of the Ts. The film grown at a Ts of 252°C showed the highest Tc,onset value of 27.8 K and had a sharp transition (ΔTc=0.5 K) in the resistivity.