Westinghouse Electric Corporation

The United States of America As Represented by the United States

Charles S Duncan

Paul A Piotrowski

Edgar L Kochka

Raymond G Seidensticker

James P McHugh

Richard H Hopkins

Maria E Skutch

A lid for a susceptor in which a crystalline material is melted by induction heating to form a pool or melt of molten material from which a dendritic web of essentially a single crystal of the material is pulled through an elongated slot in the lid and the lid has a pair of generally round openings adjacent the ends of the slot and a groove extends between each opening and the end of the slot. The grooves extend from the outboard surface of the lid to adjacent the inboard surface providing a strip contiguous with the inboard surface of the lid to produce generally uniform radiational heat loss across the width of the dendritic web adjacent the inboard surface of the lid to reduce thermal stresses in the web and facilitate the growth of wider webs at a greater withdrawal rate.

Lid for improved dendritic web growth

This invention delineates a multiple barrier design for separating the feed compartment (12) from the growth compartment (13) in crucibles (10) used for silicon dendritic web growth. The use of the barrier design greatly reduces the thermal interaction between the two compartments permitting larger replenishment rates without adverse effect on crystal growth. Its novelty lies in having a primary and secondary barrier (15,16) spaced apart from one another such that there exists a space (22) between the barriers (15,16) which is devoid of liquid silicon thus reducing the thermal conductance of the combination.

Barrier design for crucibles for silicon dendritic web growth

This disclosure describes an apparatus to improve the web growth attainable from prior web growth configurations. This apparatus modifies the heat loss at the growth interface in a manner that minimizes thickness variations across the web, especially regions of the web adjacent to the two bounding dendrites. In the unmodified configuration, thinned regions of web, adjacent to the dendrites, were found to be the origin of crystal degradation which ultimately led to termination of the web growth. According to the present invention, thinning adjacent to the dendrites is reduced and the incidence of crystal degradation is similarly reduced.

Apparatus for silicon web growth of higher output and improved growth

The concept of this invention is to provide a thermal geometry which produces web growth at a constant width by balancing the heat loss pattern from the growing dendrites in such a manner that the outer requirements for stable web growth are simultaneously met. This is accomplished by configuring the geometry of the growth system such that the heat loss pattern from the growing web, the heat loss pattern from the growing dendrites, and the temperature profile in the melt can each be controlled independently and simultaneously optimized.

Apparatus for growing dendritic web crystals of constant width

A crucible/susceptor system is described in which the walls of the crucible and the susceptor cavity are sloped outward in an angle sufficient for the force of gravity to exceed the inward pulling forces created by the high surface tension of molten silicon allowing the softened quartz crucible walls to settle into and form to the sloped walls of the susceptor thereby improving heat transfer from the susceptor to the molten silicon and improving the reproducibility of the system.

Conforming crucible/susceptor system for silicon crystal growth

A melt system including a susceptor-crucible assembly having improved gradient control when melt replenishment is used during dendritic web growth. The improvement lies in the formation of a thermal barrier in the base of the receptor which is in the form of a vertical slot in the region of the susceptor underlying the crucible at the location of a compartmental separator dividing the crucible into a growth compartment and a melt replenishment compartment. The result achieved is a step change in temperature gradient in the melt thereby providing a more uniform temperature in the growth compartment from which the dendritic web is drawn.

Apparatus for growing a dendritic web

A method and apparatus for controlling the diameter of single crystals grown by the Czochralski process in which an infrared sensor determines the temperatures of the melt adjacent to the crystal and a control circuit compares an average of these temperatures to a reference temperature to provide an error signal which controls the inductive heating of the melt.

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Penn Hills, PA, United States of America

Charles S Duncan