Charles James Duncan

US Patent:

43893775, Jun 21, 1983

Filed:

Jul 10, 1981

Appl. No.:

6/282334

Inventors:

Charles S. Duncan - Pittsburgh PA
Paul A. Piotrowski - Monroeville PA
Maria E. Skutch - Trafford PA
James P. McHugh - Pittsburgh PA

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

C30B 1510

US Classification:

422246

Abstract:

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.

US Patent:

47477741, May 31, 1988

Filed:

Feb 9, 1987

Appl. No.:

7/012779

Inventors:

Paul A. Piotrowski - Monroeville PA
Edgar L. Kochka - Greentree PA
Charles S. Duncan - Penn Hills PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

F27B 1400

US Classification:

432156

Abstract:

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.

US Patent:

49199013, Apr 24, 1990

Filed:

Dec 31, 1987

Appl. No.:

7/140071

Inventors:

Raymond G. Seidensticker - Forest Hills PA
Edgar L. Kochka - Greentree PA
Charles S. Duncan - Penn Hills PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

C30B 3500

US Classification:

422249

Abstract:

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.

US Patent:

50982877, Mar 24, 1992

Filed:

Mar 16, 1990

Appl. No.:

7/525205

Inventors:

Charles S. Duncan - Penn Hills PA
Edgar L. Kochka - Greentree PA
Paul A. Piotrowski - Monroeville PA
Raymond G. Seidensticker - Forest Hills PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

F27B 1410

US Classification:

432262

Abstract:

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.

US Patent:

48288080, May 9, 1989

Filed:

Sep 2, 1987

Appl. No.:

7/092796

Inventors:

Charles S. Duncan - Penn Hills PA
Paul A. Piotrowski - Monroeville PA

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

C30B 2702

US Classification:

422249

Abstract:

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.