Improvement of GaAs Crystal Quality by Means of Liquid-Solid Interface Curvature Control.

Abstract

A solid-convex condition of growth of GaAs single crystal from the melt is sought, so that crystal quality may improve as a function of length. The first year's work reported earlier that the thermal contour changes as a function of the sample's tip position. The second year effort reported here shows that the problem associated with thermal conductivity discontinuity, which can be lessened, is minor. The major problems associated with the vertical, contained, directional freezing technique with solid convex thermal contour are inherent and uncompromising. These are large axial temperature gradient, radial gradient, difference in thermal expansion coefficients, and convection. These effects lead to quartz container breakage, nonstoichiometry and polycrystallinity. The difficulties far outweigh the possible benefits from the liquid-solid interface curvature control and no further work along this line is recommended.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1978
Accession Number
ADA072706

Entities

People

  • W. Tantraporn

Organizations

  • General Electric

Tags

Communities of Interest

  • Advanced Electronics
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Coefficients
  • Conductivity
  • Containers
  • Convection
  • Critical Temperature
  • Crystals
  • Curvature
  • Discontinuities
  • Furnaces
  • Heat Energy
  • Measurement
  • Melting Point
  • Phase
  • Single Crystals
  • Temperature Gradients
  • Thermal Conductivity
  • Transition Temperature

Readers

  • Fluid Mechanics and Fluid Dynamics.
  • Materials Science and Engineering.
  • Systems Analysis and Design