Young's modulus E-f and hardness H-f of Pd thin films were measured by the nano-indentation technique. Pd films were made under various conditions with the film thickness t(f) varied from 20 to 280 nm and deposition temperature T-s, from 25 to 360 degrees C in vacuum. As an independent check, the Young's modulus < E-f> of some selected Pd films was measured again by the X-ray diffraction plus stress measurement. The values of E-f and < E-f> in general agree with each other for the same Pd film. The surface morphology of each film was examined by an atomic force microscope, and the surface roughness parameters, such as S-q and S-a, were calculated. From X-ray diffraction studies we estimated the grain size D and the ratio I-111/I-200, where I-111 and 1200 are the peak amplitudes of the (111) and (200) diffraction lines, of the Pd films. We also find that both E-f and H-f are dependent on t(f). In short, Ef increases when 20 nm < t(f) < 196 nm, reaches a maximum at t(f) = 196 nm, and decreases afterwards, while Hf decreases monotonically with increasing t(f). The E-f data are analyzed based on the structural properties, such as the ratio I-111/I-200 and the density delta, of each Pd film. The H-f data are discussed based on the t(f) dependence of grain size D. Finally, the conditions required to make a good nano-indentation measurement on a thin-film sample are summarized. (c) 2005 Elsevier B.V. All rights reserved.