NASA Logo, External Link
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed AddThis share icon
 

Record Details

Record 64 of 1274
Rate limits in silicon sheet growth - The connections between vertical and horizontal methods
External Online Source: doi:10.1016/0022-0248(87)90157-6
Author and Affiliation:
Thomas, Paul D.(Massachusetts Inst. of Tech., Cambridge, MA, United States)
Brown, Robert A.(MIT, Cambridge, MA, United States)
Abstract: Meniscus-defined techniques for the growth of thin silicon sheets fall into two categories: vertical and horizontal growth. The interactions of the temperature field and the crystal shape are analyzed for both methods using two-dimensional finite-element models which include heat transfer and capillarity. Heat transfer in vertical growth systems is dominated by conduction in the melt and the crystal, with almost flat melt/crystal interfaces that are perpendicular to the direction of growth. The high axial temperature gradients characteristic of vertical growth lead to high thermal stresses. The maximum growth rate is also limited by capillarity which can restrict the conduction of heat from the melt into the crystal. In horizontal growth the melt/crystal interface stretches across the surface of the melt pool many times the crystal thickness, and low growth rates are achievable with careful temperature control. With a moderate axial temperature gradient in the sheet a substantial portion of the latent heat conducts along the sheet and the surface of the melt pool becomes supercooled, leading to dendritic growth. The thermal supercooling is surpressed by lowering the axial gradient in the crystal; this configuration is the most desirable for the growth of high quality crystals. An expression derived from scaling analysis relating the growth rate and the crucible temperature is shown to be reliable for horizontal growth.
Publication Date: Mar 01, 1987
Document ID:
19870049903
(Acquired Nov 28, 1995)
Accession Number: 87A37177
Subject Category: SOLID-STATE PHYSICS
Document Type: Journal Article
Publication Information: Journal of Crystal Growth; p. 1-9; (ISSN 0022-0248); 82; 1-2,
Publisher Information: Netherlands
Contract/Grant/Task Num: NAS7-918
Financial Sponsor: NASA; United States
Organization Source: Massachusetts Inst. of Tech.; Cambridge, MA, United States
Description: 9p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: HEAT TRANSFER; LIQUID-SOLID INTERFACES; MELTS (CRYSTAL GROWTH); SILICON; TEMPERATURE DISTRIBUTION; DENDRITIC CRYSTALS; POLYCRYSTALS; SPACE COMMERCIALIZATION; TEMPERATURE GRADIENTS; TWO DIMENSIONAL MODELS
Imprint And Other Notes: (Magyar Tudomanyos Akademia, International Union of Crystallography, and Eotvos Lorand Fizikai Tarsulat, International Symposium on Shaped Crystal Growth, 1st, Budapest, Hungary, July 22-25, 1986) Journal of Crystal Growth (ISSN 0022-0248), vol. 82, no. 1-2, March 1987, p. 1-9. Research supported by the Mobil Foundation.
Miscellaneous Notes: Research supported by the Mobil Foundati
Availability Source: Other Sources
› Back to Top
Find Similar Records
NASA Logo, External Link
NASA Official: Gerald Steeman
Site Curator: STI Program
Last Modified: August 18, 2011
Contact Us