PROCEDURE FOR GROWTH OF CdZnTe BY METHOD OF AHF (AXIAL HEAT FRONT), WHERE 0≤x≤1 OF DIAMETRE TO 150 mm Russian patent published in 2011 - IPC C30B13/18 C30B15/08 C30B29/48 

FIELD: metallurgy.

SUBSTANCE: crystals Cd_1-xZn_xTe are grown at high pressure of inert gas under conditions of axial heat flow near front of crystallisation by procedure of axial heat front (AHF) with use of phone heater immersed into melt of heater - AHF heater. The procedure consists in drawing crucible with melt in a cold zone at rate v at different initial compositions of charge in the zone of crystallisation W₁ at thickness of layer of melt h and in a feed zone W₂. Also, source components Cd, Zn, Te or preliminary synthesised compounds CdTe and ZnTe are placed in zone W₁ (14) at ratio facilitating correspondence of melt composition to required composition on a liquidus curve before beginning of the AHF-crystallisation, and in zone W₂ (15) - source components Cd, Zn, Te or preliminary synthesized compounds CdTe and ZnTe at ratio facilitating correspondence of melt composition to required composition on solidus curve. Control of transfer of weight in the crystallization zone W_i is achieved owing to choice of optimal ratio between axial gradient of temperature in melt gradT_ax at height of melt h and radial distribution of temperature along the AHF-heater determined by two-dimension numerical model depending of diametre of crystal and required quality. A multi-sectional AHF-heater (5) or immersed partition (20) and multi-sectional phone heater (4) are used for control over distribution of temperature in working volume. Control is carried out by readings of thermo-sensors (8, 9, 10, 11). Additional circular heater (12) installed near a wall of crucible opposite to the AHF heater with heat-sensor (13) is used for control over form of crystallisation front. Depending on required quality of crystal and diametre of crucible crystallisation is carried at the following parametres: h=0.5-40 mm, axial gradient of temperature near crystallisation front gradT_ax=3-120°C/cm, rate of drawing out crucible with growing crystal v=0.1-10 mm/hour, temperature drop along the AHF-heater T₂-T₁=0-6°C, temperature drop between side surface of crucible and periphery of the AHF-heater T₆-T₂=:0.5-20°C. Average density of etching pits is 5*10² cm^-2 to crystal annealing.

EFFECT: high degree of macro- and micro-uniformity of grown crystals CZT of big diametre.

22 cl, 2 dwg