%0 Journal Article
%A Ramamoorthy Ramesh
%A A Inam
%A D.M Hwang
%A T.D Sands
%A C.C Chang
%A D.L Hart
%B Applied Physics Letters
%D 1991
%G eng
%P 1557-1559
%R 10.1063/1.105176
%T Surface outgrowth problem in c-axis oriented Y-Ba-Cu-O superconducting thin films
%V 58
%X The origin of surface outgrowths in c-axis oriented superconducting Y-Ba-Cu-O thin films has been identified. We find that a,b-axis regions nucleate heterogeneously at second phase regions and rapidly grow outward, leading to the formation of lenticular-shaped outgrowths. The second phase has been identified by electron diffraction and high-resolution electron microscopy to be the Y1Ba3Cu2O7-x phase that forms as microscopic platelet-shaped precipitates on the a-b plane. The heterogeneous nucleation of such outgrowths is general and has been observed in both in situ sputtered and laser-deposited films. It is probably related to the ledge growth mechanism of the c-axis oriented Y-Ba-Cu-O thin film and to the precise overall composition of the film and needs to be studied in detail in order to produce films with smooth surfaces.