Investigation of the structure of thin HfO₂films by soft x-ray reflectometry techniques

Abstract

HfO(2) thin films of different thicknesses and deposited by two methods (ALD and MOCVD) were studied. The microstructure of films was characterized by reflection spectroscopy, x-ray diffraction (XRD), and soft x-ray reflectometry. It was established that the HfO(2) film microstructure is closely dependent on film thickness. The 5 nm thick film synthesized by ALD shows an amorphous phase while the film prepared by MOCVD was inhomogeneous in depth and showed signs of crystalline structure. First results on the reconstruction of the depth distribution of chemical elements based on the analysis of reflectivity curves are discussed.

Soft x-ray reflectometry, hard x-ray photoelectron spectroscopy and transmission electron microscopy investigations of the internal structure of TiO2(Ti)/SiO2/Si stacks

“…Then the atomic concentration profiles C j (z) of all the involved elements are reconstructed by fitting all the experimental curves simultaneously. The first attempt demonstrating such a reconstruction is described in [25].…”

General laws of X-ray reflection from rough surfaces: II. Conformal roughness

“…This profile, although somewhat deformed, is close to the initial permittivity distribution. The above example clearly demonstrates 4 sin θ that, when solving the inverse problem of reflectome try, a measurement of the total reflection coefficient instead of the specular reflection coefficient allows one to significantly increase the accuracy of recon structing the permittivity profile, even when roughness effects are not taken into account explicitly. There is another (even more important reason) for which the measurements of the total reflection coeffi cient are necessary to solve the inverse problem of reflectometry.…”

“…Currently, measurements of angular and spectral dependences of hard and soft X ray reflection coeffi cients are widely used to study the surface layers of var ious materials and make it possible to determine the distributions of permittivity [1][2][3], the atomic con centrations of chemical elements [4], and the chemi cal bond structure in materials [4,5] with a subna nometer depth resolution.…”

The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II

“…It enables atomic concentration profiles (Filatova et al, 2012 to be reconstructed, polarization dependence and anisotropy effects of helical substances to be investigated (Filatova & Lukyanov, 2002;Filatova et al, 2005), and information about roughness of surface and buried interface structures to be obtained (Konyushenko et al, 2014). Based on accurate reflection coefficient spectra it is possible to calculate the spectral dependence of optical constants (Filatova et al, 1999(Filatova et al, , 2009b.…”