Інститут фізики напівпровідників ім. В.Є. Лашкарьова НАН України
Національна академія наук України


Crystals of optical Germanium

№34 Development Division and fluctuation analysis of semiconductor materials and structures
   G.S. Pekar

• melt-grown crystals of optical germanium in calibrated rods up to 250 mm in diameter or in rectangular blocks up to 120x120x60 mm3 in size;
• pre-shaped blanks (cut, ground, or pre-polished).

023 023 2

The optical absorption coefficient of grown optical germanium crystals doesn't exceed 0.02 cm-1 in the 2 to 11 μm range. The optical transmittance of the 5-mm thick polished window is no less than 46,5 % at room temperature (see the figure). Dispersion of IR radiation in the crystals does not exceed 1,5 %.

In contrast to production of other companies, the proposed crystals does not contain Stibium as a dopant

We are engaged in crystal growing during four decades. In the past this work was carried out by special Joint Laboratory of the Ministry of Electronic Industry of the USSR and of the Ukrainian Academy of Sciences. This laboratory, headed by Prof. G.Pekar, included highly skilled scientists, engineers and technicians. Now this staff is free to pursue commercial projects on growing and delivery of semiconductor materials. As to optical germanium production, we use the original technological methods developed by us as well as the following equipment:

• equipment for germanium dioxide production from enriched ash;
• equipment for germanium dioxide reduction;
• equipment for floatzone purification of germanium;
• growers of different types (including Czochralski and Bridgman growers);
• equipment for testing and metrology (semiconductor N and P typing, electrical resistivity, optical transmission, X-ray analysis, microhardness, etc.);
• equipment for crystal calibration, cutting, lapping and polishing.

Since 1998, the crystals of optical germanium and some types of blanks for germanium optical elements have been delivered to the U.S.A., Germany, Austria and Russia against long-term contracts.