Macrosegregation in the growth of doped III‐V‐semiconductors from the solution

Abstract

In case of the solution growth of S-doped InP bulk crystals from the In solution the solutal convection plays the dominant role for the transport of matter even under microgravity conditions. A measure for the strength of convection is the macrosegregation. For various boundary conditions the axial segregation is described with modified classical segregation models. The measured and calculated physical parameters such as effective distribution and diffusion coefficients respectively allow a consistent formulation of macro-and microsegragtion. Dedicated to Professor K. W. Benz on the occasion of his 65th birthday.

Melt Structural Self-Organization and Viscosity within the Transient Layer during a Single Crystal Growth in Microgravity

“…3). It is shown [10], that for Ge and GaSb this parameter is conservative enough and as a first approximation it does not depend on the dopant sort been ranging from 6.2×10 17 to 7.0×10 17 . The cluster forming process near the crystallization front is shown to be actively proceed in the area limited by isotherms [T m ; T m +10K] with the integral (effective) viscosity of the melt (ν*) being able to rise by an order of magnitude (up to about 60 times higher).…”

“…Its behavior in the process of crystal growth is analogous to that of impurities with K S >1; at the interface it creates a depleted melt-solution layer with the lower equilibrium crystallization temperature. Since the δ-layer thickness and the concentration profile are both highly dependent on the intensity of diffusion and/or convective heatmass transfer within the liquid zone, the process of А 3 В 5 crystallization from the melt-solution is extremely gravity-sensitive [17]. Besides impurity inhomogeneity (if a doped melt was used) this sensitivity also manifests itself in the single crystal intrinsic structural perfection.…”

“…Besides impurity inhomogeneity (if a doped melt was used) this sensitivity also manifests itself in the single crystal intrinsic structural perfection. A study has been carried out of reference-and two space-grown single crystals of InP:S grown from the melt whose initial composition was ≈84 at.% indium, ≈16 at.% phosphorus and 2.2×10 18 at/cm 3 sulfur onboard Photon-11 orbiter under the Russian-German SKAT-FD program [17,18]. The consequences of a developing diffusion mode are: the δ-layer depleted in phosphorus and unsteady; early development of a crystal cellular substructure; phase structuring of the transient layer with formation of microdefects observed in space-grown crystals (Fig.…”