The following operators can be used to better focus your queries.
( ) , AND, OR, NOT, W/#
? single char wildcard, not at start
* multi char wildcard, not at start
(Cat? OR feline) AND NOT dog?
Cat? W/5 behavior
(Cat? OR feline) AND traits
Cat AND charact*
This guide provides a more detailed description of the syntax that is supported along with examples.
This search box also supports the look-up of an IP.com Digital Signature (also referred to as Fingerprint); enter the 72-, 48-, or 32-character code to retrieve details of the associated file or submission.
Concept Search - What can I type?
For a concept search, you can enter phrases, sentences, or full paragraphs in English. For example, copy and paste the abstract of a patent application or paragraphs from an article.
Concept search eliminates the need for complex Boolean syntax to inform retrieval. Our Semantic Gist engine uses advanced cognitive semantic analysis to extract the meaning of data. This reduces the chances of missing valuable information, that may result from traditional keyword searching.
The oxygen concentration of silicon crystals pulled from a melt is controlled using melt rotation induced by the magnetic field of the three-phase resistance heaters used to heat the melt.
English (United States)
This text was extracted from a PDF file.
This is the abbreviated version, containing approximately
53% of the total text.
Page 1 of 2
Controlling the Oxygen Concentration of Silicon Crystals by Magnetically
Induced Melt Rotation
The oxygen concentration of silicon crystals pulled from a melt is controlled
using melt rotation induced by the magnetic field of the three-phase resistance
heaters used to heat the melt.
Control of the oxygen concentration of silicon crystals is necessary to obtain
optimum device performance and yields from subsequent device manufacturing
processes performed on slices or wafers from these crystals.
The oxygen concentration of crystals grown by the Czochralski method is
derived from the reaction or dissolution of the fused quartz crucible by the molten
silicon. The actual concentration of oxygen in any portion of the crystal is
determined by the concentration of oxygen dissolved in the melt at the time that
portion of the crystal was solidified.
Significant alteration of the steady-state oxygen concentration of the melt can
only be accomplished by altering the rate of dissolution of the crucible.
The rate of dissolution of the crucible is determined by the temperature at the
melt-crucible interface and by the rate of removal of the solute (oxygen) from the
concentration boundary layer which forms in the thin layer of melt in contact with
the crucible. If no stirring of the melt occurs, then the rate of the dissolution
quickly falls to a rate determined by the rate of diffusion of the solute from the
Significant changes in the oxygen concentration of the melt can be
accomplished by altering the rate of shear between the melt and the crucible.
This has been accomplished in the past by altering either the thermal gradients,
thereby altering the rate of thermal convective motion of the melt, or by abruptly
changing the angular velocity of the crucible with respect to the melt by
intermittently rotating, then stopping, then rotating the crucible, utilizing the inertia
of the melt to obtain shearing action between melt and crucible.
This process utilizes a completely different mechanism for accomplishing the
shearing action between the melt and the crucible surface in contact with it.