公开(公告)号：US3689242A

公开(公告)日：1972-09-05

申请号：US3689242D

申请日：1970-02-16

Applicant: MASSACHUSETTS INST TECHNOLOGY

Inventor： PLATAKIS NICOLAOS S ,  GATOS HARRY C ,  WITT AUGUST F

IPC: C03B5/033 ,  C03B19/02 ,  C03B19/04 ,  C03B19/09 ,  H01L45/00 ,  H01S3/17 ,  C03B29/00 ,  C03B5/16

CPC classification number: H01S3/17 ,  C03B5/0338 ,  C03B19/02 ,  C03B19/04 ,  C03B19/095 ,  C03B2201/86

Abstract: A METHOD IS DISCLOSED FOR PREPARING AN ELECTRICALLY AND OPTICALLY ACTIVE MATERIAL, EITHER VITEOUS OR POLYCRYSTALLINE, THAT PROVIDES A MATERIAL THAT IS NON-POROUS, CONTAINS NO INCLUSIONS, IS CHEMICALLY HOMOGENEOUS, AND ONE THAT CAN BE CUT OR OTHERWISE FORMED TO SOME DESIRED UNIFORM GEOMETRICAL SHAPE. THE PROCESS DISCLOSED INCLUDES SUBJECTING THE COMPONENTS OF THE MATERIAL HELD WITHIN A SEALED AMPOULE OR OTHER CLOSED CONTAINER TO AN ELEVATED TEMPERATURE IN AN INERT ATMOSPHERE OR VACUUM FOR A TIME PERIOD LONG ENOUGH FOR THE COMPONENTS TO BECOME MOLTEN AND TO REACT CHEMICALLY WITH ONE ANOTHER. HEATO IS THEN WITHDRAWN FORM THE MOLTEN MATERIAL TO LOWER THE TEMPERATURE TO A VALUE AT WHICH A THIN LAYER OF MOLTEN MATERIALS ADHERES TO THE INNER SURFACE OF THE CONTAINER. RELATIVE MOVEMENT IS EFFECTED BETWEEN THE BULK OF THE MOLTEN MATERIAL AND THE THIN LAYER OF MELT THAT ADHERED TO THE INNER SURFACE, THE THIN LAYER BEING MOVED AWAY FROM THE BULK OF THE MELT TO ALLOW SOLIDICICATION THEREBY TO FORM A SOLIDIFIED LAYER. THE SOLIDIFIED LAYER IS ALTERNATELY BROUGHT INTO CONTACT WITH THE BULK OF THE MOLTEN MATERIAL TO PICK UP A THIN LAYER OF MELT AND REMOVED FROM SUCH CONTACT TO ALLOW THE THIN LAYER TO SOLIDIFY, THERE BEING A CONTINUED WITHDRAWAL OF HEAT FROM THE REGION OCCUPIED BY THE AMPOULE IN ORDER THAT THE SOLID LAYER WILL INCREASE IN THICKNESS LAYER UPON LAYER AS ADDITIONAL MOLTEN MATERIAL SOLIFIFIES.