Combined molecular beam epitaxy and diffractometer system for in situ x-ray studies of crystal growth

Abstract

A combination of a molecular beam epitaxy (MBE) machine and a six circle diffractometer has been constructed at a dedicated wiggler beamline at the storage ring BESSY II for in situ investigations of III–V compound crystal growth. The growth conditions in our system reach a high MBE standard with a noncooled base pressure of 2×10−10 mbar. A fast entry load lock is available for sample exchange. Large-area Be windows in the ultrahigh vacuum chamber allow us to measure reflections at entrance and exit angles up to 45°, i.e., large perpendicular momentum transfers are possible. In situ reflection high energy electron diffraction and x-ray fluorescence measurements can be performed simultaneously with x-ray scattering. A GaAs(001) surface prepared and examined in our system reveals terrace widths of 450 nm and β(2×4) reconstruction domain sizes of 210 nm. The possibility of time-resolved x-ray diffraction studies is demonstrated by observation of intensity oscillations during layer-by-layer homoepitaxial growth on the GaAs(001)β(2×4) surface. The resolution functions of our experiment are determined.

Endotaxy of MnSb into GaSb

“…The samples were grown in the PHARAO facility at the synchrotron BESSY in Berlin, Germany, in a chamber that allows in situ synchrotron X-ray diffraction with 10 keV beam during growth [4]. The 1 mm thick GaSb(0 0 1) substrates were prepared for growth by desorbing the (epiready) native oxide at 530 AE 10 C under an Sb flux.…”

Quantitative structure determination of GaAs(001) under typical MBE conditions using synchrotron X-ray diffraction

“…The sheet can be heated up to 250 1C using an electric current. A similar apparatus is now in operation at BESSY, Germany [5].…”

Growth of praseodymium oxide and silicate for high-k dielectrics by molecular beam epitaxy

“…Since Pr 2 O 3 is not stable in air, the samples are transferred through a UHV shuttle to the other UHV chamber for measuring X-ray diffraction. The in-plane grazing incidence X-ray diffraction (GIXRD) is performed with 10 keV X-rays at the PHARAO beamline [10] at the synchrotron BESSY in Berlin, Germany. Before measuring X-ray reflectivity (XRR) and electrical properties, a polycrystalline Si layer is deposited on top of the Pr 2 O 3 layer in order to prevent reactions with air when removing the sample from the UHV chamber.…”