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著者人数: 21名, Accepted: 2015-02-24

We are preparing for crystal growth experiments in microgravity using Gradient Heating Furnace (GHF). The one-dimensional Traveling Liquidus-Zone (TLZ) growth model is limited by the radial temperature gradient, convection in a melt and so on. Such factors affecting one-dimensionality are studied experimentally and theoretically. Reaction between the melt and cartridge materials is being investigated for analyzing safety requirements and for designing flight cartridges. Here, achievements in the present preparatory stage are reported.

The TLZ method is a new crystal growth method which has been invented for the growth of homogeneous mixed crystals. The influence of convection in a melt on the compositional homogeneity of TLZ-grown In(x)Ga(1-x)As crystals was investigated by the growth of various diameter crystals on the ground. The results have shown that excellent compositional homogeneity is realized even on the ground if the crystal diameter is less than 2 mm and convection in a melt is suppressed. However, such small diameter crystals cannot be used for device application. Then, the plate crystal growth for obtaining large surface area was tried since the limitation of the thickness of plate crystal was useful for suppressing convection in a melt. In(0.3)Ga(0.7)As plate crystals with 10 mm width and 2 mm thickness showed good compositional homogeneity as expected but the grown crystals were poly crystals. Single crystallization of plate crystals is required for device fabrication and the effort was made to grow plate-like In(0.3)Ga(0.7)As single crystals. Those results obtained in this study in the fiscal year of 2003 is reported here., JAXA Research and Development Report, 宇宙航空研究開発機構研究開発報告

We have succeeded in scaling up of platy In(0.1)Ga(0.9)As single crystals grown by the traveling liquidus-zone (TLZ) method from 10 to 20 mm in width without deteriorating compositional uniformity. The TLZ method which we have invented for growing homogeneous mixed crystals requires diffusion-limited mass transport and convection in a melt should be avoided. In that point, large diameter crystals for substrate use were difficult to be grown on the ground because convection in a melt is intensified by the enlargement of diameter. Therefore, we attempted to grow platy In(1-x)Ga(x)As crystals. Merits of platy crystals are suppression of convection in a melt by limiting the thickness of the melt and achievement of sufficient area for substrate use. Successful scaling up of platy crystals shows that enlargement of the width of platy crystals will not affect the intensity of convection in a melt. This result supports the hypothesis that convection in a platy melt is limited by its small thickness and not by its width., JAXA Special Publication, 宇宙航空研究開発機構特別資料

In the growth of In(0.3)Ga(0.7)As single crystals, polycrystallization at the initial interface with lattice-mismatched seeds is a major problem because no homogeneous In(0.3)Ga(0.7)As seed crystals have been obtained and usually GaAs crystals are used as seeds. Hence, a mechanism of polycrystallization at the initial interface was investigated. In this paper, a local misfit stress at the interface is calculated. Then it is compared with the critical resolved shear stress (CRSS). It was determined that the polycrystallization at the initial interface is related to the magnitude of the misfit stress and to that of the CRSS. We discuss growth of larger In(0.3)Ga(0.7)As single crystals by avoiding the polycrystallization at the initial interface., JAXA Special Publication, 宇宙航空研究開発機構特別資料