Growth of Niobium Thin Films on Si Substrates by Pulsed Nd:YAG Laser Deposition

The growth of Nb thin films on Si(100) substrates by pulsed Nd:YAG laser deposition (PLD) under different laser fluences (4-15 J/cm2) was reported. The influence of laser fluence on ablation rate and deposition rate was discussed. X-ray diffraction (XRD) investigations of the deposited films showed an amorphous structure. The droplet density on the film surface observed by scanning electron microscopy (SEM) analyses was extremely low. It was experimentally proved that the droplets on the film surface originated from liquid phase on the target surface. Profilometric measurements of the deposited Nb films revealed a substantial asymmetry in the film thickness related to the plume deflection effect. The measured electrical resistivity of the Nb film was higher than that of high purity Nb bulk. The present investigations of ablation and deposition process of Nb thin films are related to its potential application in superconducting radio-frequency (SRF) cavities.