Interfacial roughness of sputtered multilayers: Nb/Si

Abstract

We have carried out studies of the interfacial roughness of a number of Nb/a-Si multilayers using cross-section transmission electron microscopy, wide-angle x-ray diffraction, and low-angle x-ray reflectivity and diffuse scattering. The multilayers studied were grown by sputtering in an Ar atmosphere at various pressures. The effect of the layer thickness and of the number of layers has also been studied. We observed a clear transition in the growth morphology when the sputtering pressure is raised above the thermalization pressure ( =9 mTorr) of the sputtered atoms. Both the mosaic of the Nb crystallites and the interface roughness increase dramatically when the Ar pressure exceeds 9 mTorr. The roughness of the various interfaces is strongly conformal and the samples with large roughness show a roughness that increases with deposited layer number. We discuss the quantitative extraction of these parameters from the x-ray data and the implications of these results for the physics of the deposition process.

Structure and transport properties of coherently strained La2/3Ca1/3MnO3/SrTiO3 superlattices

“…The peaking of the diffuse intensity at the same Bragg condition for all different offset values clearly demonstrates that there is indeed vertically correlated roughness in the superlattice. A systematic broadening of the peak widths with increasing offset values was also observed [30].…”

Surface and structural disorder in MBE and sputtering deposited Cu thin films revealed by X-ray measurements

“…This is commonly observed in the case of multilayers [18,20], where the roughness can propagate periodically along the growth direction reinforcing the diffuse intensity in correspondence of the Bragg reflections. In the case of single layers, the presence of correlated roughness between the substrate and the film surface gives rise to the observed weak increase of the diffuse intensity [19,21].…”

Resonant Soft X‐Ray Techniques to Resolve Nanoscale Magnetism

“…While domains mediate reversal in each film, their remanence and coercivity depend sensitively on the relative amount of microstructural disorder that in turn depends on the sputter pressure. Films deposited at lower pressure tend to be smoother than those deposited at higher pressure; the extreme roughness limit corresponds to columnar growth of polycrystalline grains with voided grain boundaries, while the smooth limit corresponds to a polycrystalline microstructure with dense grain boundaries and a relatively smooth surface topography [105]. Speckle metrology reveals that the extent of microscopic magnetic memory is dramatically different depending on the growth-induced disorder in these films.…”