THE ROLE OF RADICALS AND CLUSTERS IN THERMAL PLASMA FLASH EVAPORATIONPROCESSING

The prominent features of plasma flash evaporation may be caused by cl uster deposition under high net flux of radicals. In order to clarify such features quantitatively, the atomic oxygen flux (Gamma(o)) and cl uster size (d) in 200 Torr RF thermal Ar-O-2 plasma were measured on t he substrate. It was found that Gamma(o) higher than 10(19) atoms/cm(2 )-s can be easily achieved in this processing and this value correspon ds to frozen atomic oxygen fraction 7%. The cluster size of YBCO was e stimated to be about 0.3 to 10 nm. 0.8 nm cluster deposition under Gam ma(o) higher than 6 x 10(18) atoms/cm(2)-s made it possible to deposit fine epitaxial YBCO films with Tc = 90K on SrTiO3 (100) with extremel y high deposition rate around 2.2 mu m/min.