Large area deposition of YBa2Cu3O7−x films by pulsed laser ablation

A special patented design is built up to produce homogeneous YBa2Cu3O7−x (YBCO) films by pulsed laser deposition (PLD) over areas as large as 7×20 cm2. The use of a line focus (8 cm) reduces the substrate movement to one dimension. The demands on plasma homogenization, substrate scanning and film temperature during the deposition process for large area PLD are discussed and their technical realization is presented. First results of 1×1 cm2 YBCO films at different positions on the substrate holder (11×28 cm2) show homogeneous deposition conditions. The transition temperatures of the deposited YBCO thin films on 1×1 cm2 SrTiO3 substrates are TC=89 K with critical currents of 4×106 A/cm2 at T=77 K. The structural properties of these films (χmin=4.5%) indicate also their high crystalline quality. The variation of film thickness perpendicular to the scanning direction is less than ±9% and along the scanning direction ±7%.