Papers by Keyword: Growth Interface

Abstract: The shape and stability of growth interface have significant influence on the floating zone (for short FZ) silicon crystal. During the growth of crystal cone, growth interface reversal will happen due to the change of cooling mechanism, which makes crystal growth unstable. This impact will be more obvious for crystal with large diameter. During the growth of crystal body, with the crystal diameter increasing, the growth interface curvature and thermal stress both increase, which is easy to result in dislocation and even crack of the crystal. So this experiment mainly studied how to solve the instability problem due to interface inversion and how to reduce interface curvature. In the experiment we compared the growth interface shape of 6 inches <111> FZ silicon, at different pull speed, and find that during the growth of crystal cone, interface inversion can finish ahead with higher pull speed, and during the growth of crystal body, interface curvature decreased (interface depth≈32 mm) with lower pull speed ( υ=2.5mm/min) and higher rotate speed, to increases the chances for success of crystal growth.

Abstract: 6H-SiC ingots were grown with different growth interfaces at different rates via the sublimation method. A model for the step flow growth mechanism is proposed to interpret the occurrence of 15R-SiC inclusions in the 6H-SiC single crystal. The results show that the 15R-SiC occurs more easily on the convex and the concave interface than on the slight convex interface and 15R-SiC inclusion also occurs when the growth rate of 6H-SiC exceeds the critical rate of 300 %m/h with the slight convex interface at the seed temperature 2250°C.

Abstract: The bulk crystal growth of II-VI compounds, such as HgCdTe, CdZnTe etc., is usually carried out by Bridgman and modified Bridgman methods. Optimizing the growth process relies mainly on the understanding of the fundamental problems of solute and thermal transportation principles, which determines the composition segregations and other defects, including point defects, dislocations, precipitates, stacking faults, etc. In the last few years, the present author studied the coupling effects of the convection, thermal and solute transportation phenomena during the growth processes through both theoretical modeling and experimental methods. Several important phenomena, such as effects of ACRT forced convection on the thermal and solute field and the growth interface morphology, the shift of the growth interface due to the solute redistributions, solute segregation behaviors during the growth process, etc, are discussed. Based on these researches, technologies for growing high quality CdZnTe and other II-VI compounds have been developed.