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 a s 7 x 20 cm(2). The use of a line focus (8 cm) reduces the substrate m ovement to one dimension. The demands on plasma homogenization, substr ate scanning and film temperature during the deposition process for la rge area PLD are discussed and their technical realization is presente d. First results of 1 x 1 cm(2) YBCO films at different positions on t he substrate holder (11 x 28 cm(2)) show homogeneous deposition condit ions. The transition temperatures of the deposited YBCO thin films on 1 x 1 cm(2) SrTiO3 substrates are T-c = 89 K with critical currents of 4 x 10(6) A/cm(2) at T = 77 K. The structural properties of these fil ms (chi(min) = 4.5%) indicate also their high crystalline quality. The variation of film thickness perpendicular to the scanning direction i s less than +/-9% and along the scanning direction +/-7%. (C) 1998 Ame rican Institute of Physics.