薄膜初期成長過程に及ぼす金属シード層の効果

Abstract

Ag and Cu films were deposited by vacuum evaporation on a LiNbO3 single-crystal substrate on which surface acoustic waves (SAW) at 45 MHz were propagating. Prior to the deposition, ultra-thin Ti, Cr, Cu, and Ag films were fabricated as seed layers. The coalescence processes in an earlier stage of the film growth were investigated by measuring the SAW amplitudes during deposition. The critical thickness, at which the film structure changes from islandlike to continuous, was found to decrease with increasing seed thickness, except in the case of Cu films deposited on Ag seed layers. Ag films deposited on ultra-thin seed layers had topologically smooth surfaces in comparison with films directly deposited on the substrate. These results suggest that islands of the seed layer capture the adatoms diffused over the substrate surface and become the growth centers for the subsequent film deposition.