NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Determination of the Wetting Angle of Germanium and Germanium-Silicon Melts on Different Substrate MaterialsDuring Bridgman growth of semiconductors detachment of the crystal and the melt meniscus has occasionally been observed, mainly under microgravity (microg) conditions. An important factor for detached growth is the wetting angle of the melt with the crucible material. High contact angles are more likely to result in detachment of the growing crystal from the ampoule wall. In order to achieve detached growth of germanium (Ge) and germanium-silicon (GeSi) crystals under 1g and microg conditions, sessile drop measurements were performed to determine the most suitable ampoule material as well as temperature dependence of the surface tension for GeSi. Sapphire, fused quartz, glassy carbon, graphite, SiC, pyrolytic Boron Nitride (pBN), AIN, and diamond were used as substrates. Furthermore, different cleaning procedures and surface treatments (etching, sandblasting, etc.) of the same substrate material and their effect on the wetting behavior were studied during these experiments. pBN and AIN substrates exhibited the highest contact angles with values around 170 deg.
Document ID
19990097305
Document Type
Conference Paper
Authors
Kaiser, Natalie (NASA Marshall Space Flight Center Huntsville, AL United States)
Croell, Arne (NASA Marshall Space Flight Center Huntsville, AL United States)
Szofran, F. R. (NASA Marshall Space Flight Center Huntsville, AL United States)
Cobb. S. D. (NASA Marshall Space Flight Center Huntsville, AL United States)
Dold, P. (NASA Marshall Space Flight Center Huntsville, AL United States)
Benz, K. W. (NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1999
Subject Category
Solid-State Physics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.