Microstructural Characterization of Electrodeposited Nanocrystalline Nickel Films by X-Ray Diffraction

Nickel nanocrystalline thin films with various grain sizes were produced by electrodeposition using sulfamate solution with different brightener contents at two bath temperatures. The distribution of the grain size of deposited films was determined by Fourier profile analysis of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The grain size determined by Fourier analysis of 111-222 diffraction pairs gave smaller sizes than that of 200-400 diffraction pairs for thin films with 200 texture, while the reverse is true for films with random orientation. The distribution of grain sizes determined by TEM followed log-normal distribution. The variance was smaller for smaller sizes for both cases of XRD and TEM. The mean grain size determined by XRD of 111-222 pair agreed with that determined by TEM for sizes lower than 30 nm, while it was smaller for larger sizes. The size determined by Scherrer`s method using 111 diffraction was close to that determined by Fourier analysis of 111-222 pair, and agreed with that determined by TEM for sizes lower than 30 nm. The grain size decreased with increasing content of brightener at lower temperature of the solution bath. The yield stress of films increased with decreasing grain size, nearly following the Hall-Petch relation down to the grain size of 20 nm.