Quantitative study of interface roughness replication in multilayers using x-ray reflectivity and transmission electron microscopy

Abstract

The recently appeared distorted wave Born approximation formalism is used for quantitative determination of interface roughness replication and lateral correlation length in periodical multilayered structures. The results obtained from x-ray diffraction are in very good agreement with analysis of cross-section transmission electron micrographs. We interpret transparently the obtained parameters and demonstrate the ability of the low-angle x-ray diffraction methodology for nondestructive and quantitative studying of interface roughness in magnetic multilayers.

Transmission electron microscopy analysis of the interfaces of TiAlN/Mo multilayers

“…X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) are important tools for the study of the structural quality within the layers and at the interfaces since the microstructure is imaged with fine detail [2]. Atomic scale information on the structure of both the layers and the interfaces can be obtained as well as general features like columnar growth, grain size and orientation and interfacial roughness.…”

Roughness effect on the measurement of interface stress

“…Clearly with increasing ratio s/x (or the long wavelength roughness) the force ratio decreases, the more so for decreasing roughness exponent H which leads to rougher interfaces at shorter roughness wavelengths. Therefore, for interfaces possessing this type of roughness, as observed in a wide range of surface interface studies by X-ray reflectivity and scanning probe microscopy [12][13][14][15][18][19][20][21], the precise quantification of interface morphology is required to estimate properly the effect of roughness on the stresses in the thin film.…”

“…The nanometer scale topology of vapor-deposited single/multi-layer thin films can be quantified in many cases in terms of self-affine roughness [12][13][14][15][18][19][20][21]. In general, any physical self-affine surface or interface is characterized by a finite lateral correlation length x, an rms roughness amplitude s, and a roughness exponent H (0 Ͻ H Ͻ 1) [12][13][14][15].…”

“…Stimulated by Spaepen's work we have extended his approach to the more general cases of random self-affine and mound rough interfaces, which are commonly observed during multi-layer growth [18][19][20][21], as well as mound interface roughness that develops during epitaxial growth [8][9][10][11]22]. Our work is in both cases executed in the weak roughness limit because in many cases of thin film growth the corresponding ratio of vertical, out-of-film-plane roughness amplitude to lateral, in-plane correlation length is equal or lower than 0.1 [12][13][14][15][18][19][20][21].…”

“…Our work is in both cases executed in the weak roughness limit because in many cases of thin film growth the corresponding ratio of vertical, out-of-film-plane roughness amplitude to lateral, in-plane correlation length is equal or lower than 0.1 [12][13][14][15][18][19][20][21].…”