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Double-Crystal X-ray Diffractometer DSO-1 The X-ray double-crystal diffractometer DSO-1 is intended for the automatic high resolution characterization of the wafer structural properties: lattice perfection, lattice constants, surface deformation profile etc. It provides also the automatic measurement of crystal orientetion. Main specification of the device and conditions of operation. The general view of the device and a rocking curve example are shown in fig. 1. Three-circle goniometer - fig.2. Optical diagram - fig.3. Bartels monochromator diagram - fig.4.
Fig.1. General view of the diffractometer DSO-1 and a rocking curve of superlattice GaAs/AlAs on Ge(001) - symmetric reflection 400, CuK-alpha radiation. Upper curve - without slit in front of detector, lower one - with a slit 0.2 mm, Theta-2Theta scan. Double-crystal diffractometer DSO-1 is a not expensive, but effective decision of tasks in semiconductor materials science. Automatic 5-axes goniometer (Theta-2Theta-Phi-X-Y) on a base of reliable goniometer GUR-9 (fig.2) allows the limitation of manual adjustment actions, and provides the mapping of samples up to 6"(150 mm) in diameter. The existing of visual optic scale simplifies a goniometer referencing. The manual rotation of stepping motors allows the the sample and detector moving in a small angle range, if needed.. A large distance between a sample and monochromator (fog.3) allows a using of very big diffraction angles of monochromator (up to 80°) and a sample (up to 67°) both in symmetric and asymmetric geometry, and achieve thereby a high sensitivity to structural disorders. Original software RDPW with a macros editor provides an exclusiv flexibility in procedures of data aquisition and processing for the qualified users. On the other hand, there is a simplified interface, which allows the low qualified users a quick mastering of data aquisition in the routine measurements. The accessibility to modules in a control block provides a high repairability of diffractometer, and provides also a visual checking of modules operation by LEDs. The sound radiation indicator signifiñantly simplifies the adjustment and monitoring of diffractometer operation. The high volt generator and X-ray goniometer are controlled from PC. These two control channels are independed one from another. Alarm system, including end switches provedes a reliable biological protection of personal, and the X-ray tube protection from overheating, in a case of a fault in the water cooling system. The X-ray tube housing is intended for the European tube standard. Variable slits on the incident and the diffracted beams allow a beamforming of any geometry in the range 10x10 mm. The variable sample to detector slit distance (up to 300 mm) allows the analysis of a diffuse scattering from a sample without a crystal-analyzer by means of a narrow slit scanning. Optionally using of a Bartels monochromator (fig.4) provides a beamforming of extremely narrow spectral interval, what allows the analyzing of any single crystals without of individually selection of monochromator. The using (optionally) of a channel-cut crystal analyzer allows the realizing of a triple crystal sñheme on this diffractometer and execute a reciprocal space mapping of wafers. Specification
Diffractometer can work in laboratory conditions at temperature from 16°C up to 30°C, relative humidity up to 80% at 25°C, atmospheric pressure 100±4 kPa (750±30 mm Hg).
Fig.2. Internal view of diffractometer.
Fig.3. Optical diagram.
Fig.4. Bartels monochromator diagram.
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