Peculiarities of the thickness dependence of the superconducting properties of thin Nb films

In this report we present results of a systematical study of relevant properties of superconducting Nb thin films of thickness from 8 to 200 nm deposited on Si. We have found that a reduction of thickness d below 50 nm leads to a significant decrease of the critical temperature T-C and a strong increasing of the residual resistivity in normal state rho(0) and a strong increase of the Ginzburg-Landau magnetic penetration depth lambda(GL)(0). Taking into account the dependencies of T-C and rho(0) on the thickness of the film, we have obtained good agreement between experimental dependencies of lambda(GL)(0) on d and theoretical estimations in dirty limit for films thinner than 100 nm. (C) 2004 Elsevier B.V. All rights reserved.