16 years of serving high-end industries
with high-quality products |
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| Control of Crystalline Perfection |
 | To control the crystalline quality, Rocking curves are measured in the laboratory of State Research Scientific Institute with the X-Ray installation of super-high resolution (up to 0.1 arc-second). The incident light has the wavelength of 2.8 Angstroms. The rocking curves were measured with the help of an automated two-crystal x-ray spectrometer (CuKα1-ray, monochromator GaAs (511), monochromator angle 90.14 degrees) with a temperature stabilizing device. The spectrometer is constructed on the basis of a commercial power supply ?Iris? and a topographic camera RT-2. The rocking curves were being taken in a non-stop mode, at the angular speed of 0.0003 deg./min. We also took the symmetrical Bragg reflection from the plane of wafer areas at the angles of 90 deg. (the angle wasn?t specified). Each point size is 5 mm.
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| Below please see typical rocking curves of our substrates used for Blue LEDs applications: |
The quality of a substrate (absence of insertions, block marks, twins, dislocations and polycrystalline areas) are controlled by the width of the rocking curves. Typical curve width (at 0.5*Max level) of Kyropulos made material of the Grades 2-4 is 10-20 arc seconds (EPD<1000 per sq cm) while for Bagdasarov method it is 20-30 arc seconds (EPD<3000 per sq cm).
- chemical admixture?s concentrations,
- optical transmittance,
- surface image with AFM
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