Accession Number:

ADA237456

Title:

Development of Model Based Magnetic LP-LEC Growth Large Diameter GaAs

Descriptive Note:

Final rept. 14 Aug 1987-28 Nov 1990

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s):

Report Date:

1990-11-28

Pagination or Media Count:

105.0

Abstract:

The stated objectives of this research effort were directed at 1 The establishment of magnetic LP-LEC growth capability with diameters approaching 4 inches 2 The design of heat and mass transfer control systems required for optimization of growth with magnetic melt stabilization, and 3 Development of a model-based growth control scheme which includes complementary knowledge-based system inputs for seeding, shouldering, and growth termination. A non-invasive wafer inspection system has been developed. It is based on NIR transmission microscopy with bright and dark field illumination. It provides for rapid quantitative characterization of doped and non-doped SI GaAs on both a macro- and selected microscale. Model-based control of thermal stresses in LEC growth of GaAs has been implemented. In this approach mathematical models of the growth process and a heat exchange system are used to control the temperature field in the crystal during growth and cooldown. Crystals grown in this configuration exhibit dislocation densities in the range of 1000sq. cm. Also developed was a micro-mechanical constitutive law for high temperature creep and dislocation multiplication in GaAs.

Subject Categories:

  • Metallurgy and Metallography
  • Crystallography
  • Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE