In Situ Optical Monitoring of Two-Dimensional Crystal Growth in Layer-by-Layer Chemical Vapor Deposition of YBa2Cu3Ox

Abstract
We have applied an in situ optical growth monitoring method to layer-by-layer chemical vapor deposition of YBaCuO thin films and observed a staircaselike change in reflectance. One step corresponds to one cycle of source gas supply combination and growth of one unit cell of the YBa2Cu3O x structure. This step is completed when Cu is supplied for the third time and the final layer consisting of a unit cell is applied. This result suggests that two-dimensional crystal growth of YBa2Cu3O x occurs. The calculation of reflectance change is consistent with the hypothesis that the reflectance change is due to layer-by-layer growth of YBaCuO.