PROCESS OF CONTROL OF DIAMETER OF MONOCRYSTALS GROWN BY CZOCHRALSKI METHOD WITH LIQUID ENCAPSULATION UNDER WEIGHT CONTROL Russian patent published in 1996 - IPC

FIELD: automated growing of semiconductor monocrystals. SUBSTANCE: invention is related to field of automated growing of semiconductor monocrystals of group A₃B₅ by cZochralski method with the use of protective fluid (flux) on surface of melt, it can be also recommended for automated growing of crystals by traditional Czochralski method of growing installation with weight method of control of process. Invention makes it possible to increase accuracy of adjustment of diameter of grown monocrystal with its enlargement and after emergence of cone part of crystal from under flux by selection of program assignment in accordance with actual heat of crystallization during enlargement, low-frequency filtration of noise by means of Kalman filters and usage of two-channel control. Process consists in identification of enlargement program based on reconstruction of present values of weight signal and its derivatives with the aid of Kalman filter in the course of linear decrease of power of heating of melting pot and uncontrolled enlargement, on comparison of these values with those calculated by model of crystallization process taking into account presence of meniscus of variable volume followed by two-channel adjustment of diameter of crystal with optimum regulators in case of deviation from specified structure. EFFECT: increased accuracy of adjustment of diameter of monocrystal. 3 dwg