Malevaniy V. Development of methods of control and equipment for growing of bars of germanium of large diameter by the method of Chokhral's'kogo

Thesis deals with the actual scientific and practical problems reduce growth defects and express control of the optical properties of single crystals of germanium grown by the Czochralski method . A mathematical model of the geometry of the thermal unit , which is in contrast to other analytical parameters of the thermal unit connects to the equation of thermal radiation fluxes , which circulate between the elements of the thermal unit , which helped to solve the main task - to create the optimal design of growth vessel for growing germanium ingot diameter of 100mm and a minimum dislocation density. In our studies we used the method of photoelasticity , which gave us the opportunity to evaluate the refraction -largest internal stresses and characteristics of optical-quality single crystals of germanium. Exsperimental installation was created to determine the distribution of stress on the plane of the plate germanium. Proposed installation and control technique of internal stress will lead express control and improve the technological modes of cultivation optical germanium ingot diameter of 100 mm with improved structural and optical properties . One of the main parameters of germanium when growing ingot is their diameter, the diameter variations during growth leads to structural imperfections and the appearance of bars of plastic deformation , which leads to deterioration of optical properties of single crystals. In the developed world setting " Germanium 100 " to improve the structural characteristics of the method of measuring and maintaining a constant diameter ingot grown using the gravimetric method . For the development of automated control devices diameter ingot during growth by the Czochralski method we used a system measuring the mass of the ingot in which its mass is measured with the use of industrial load cells with hanging rod. Weight deviation from the expected value used as the error signal in the servo loop , which controls the ingot growth process heater power. In the automatic control unit diameter we used the filtering of data obtained from the load cell and the correction of disturbing factors temperature at the sensor weight, and the supply voltage variation , it gave us the opportunity to get an accuracy of measurement of the diameter of 1.5 mm. The practical relevance of these results is to introduce into production of " Status" techniques of measurement and distribution of internal stresses and express control of the optical quality single crystals of germanium , as well as the installation of growing germanium ingot diameter of 100 mm, we developed a thermal unit and automatic monitoring and support diameter grown ingots. The total annual economic impact on the implementation of this act is 42 th.