Development of X‐ray diffractometer for in‐situ observation of thin‐film crystal growth equipped with focusing monochromator

Abstract

AbstractX‐ray crystal truncation rod scattering measurement is a kind of X‐ray diffraction/scattering measurement, which is a very powerful technique to analyze interface structures quantitatively and non‐destructively. The X‐ray CTR scattering measurement can reveal layer thicknesses, distributions of atoms, surface roughness, and lattice constants at an atomic‐scale. In our previous works, synchrotron radiation (SR) has been utilized as an X‐ray source for the measurement, since it is generally considered that a strong X‐ray is necessary to measure the very weak CTR scattering signal. In this work, using a conventional X‐ray source, i.e., rotating anode X‐ray generator operated at 300 mA and 50 kV, we successfully developed an X‐ray diffractometer that can be used for the X‐ray CTR scattering measurement. The key component was a Johansson monochromator to develop the diffractometer. The Johansson monochromator was utilized both to focus X‐ray at a sample position (to make divergence angle of the incident X‐rays) and to monochromatize Cu‐Kα. By using the Johansson monochromator and a 2D‐detector, a sample was irradiated by a diverging incident X‐ray beam and the scattered X‐ray was detected at the same time. In order to suppress the noise, a Soller slit was introduced. The noise was greatly suppressed and spectrum was drastically improved by using the Soller slit. Without moving the X‐ray source, the sample, nor the detector, a reciprocal space map of a crystal can be obtained by the newly developed diffractometer, and it reduced the measurement time drastically. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)