Process for the production of large semiconductor crystals

Claim 1

A PROCESS FOR THE PRODUCTION OF LARGE, THIN CRYSTALS OF SEMICONDUCTOR MATERIAL CONSISTING ESSENTIALLY OF: (A) VACUUM EVAPORATING A LAYER OF SAID SEMICONDUCTOR MATERIAL ONTO A SUBSTANCE, SAID LAYER BEING LESS THAN ABOUT 0.1 MILLIMETER THICK; (B) DEPOSITING A LAYER OF AT LEAST ONE ACTIVATING MATERIAL SELECTED FROM THE GROUP CONSISTING OF SILVER, COPPER, ALUMINUM, INDIUM, GALLIUM, LEAD, BISMUTH, ZINC, BORON, THALLIUM, PHOSPHORUS, ARSENIC, AND ANTIMONY ONTO SAID LAYER OF SEMICONDUCTOR MATERIAL BY CONTACTING SAID LAYER OF SEMICONDUCTOR MATERIAL; THE AMOUNT OF VAPORS OF SAID ACTIVATING MATERIAL; THE AMOUNT OF ACTIVATING MATERIAL DEPOSITED BEING AT LEAST 0.001 ATOM PERCENT IN THE AGGREGATE OF THE AMOUNT OF SEMICONDUCTOR MATERIAL DEPOSITED; (C) INCREASING THE TEMPERATURE OF THE RESULTING LAYERS OF SEMICONDUCTOR MATERIAL AND ACTIVATING MATERIAL TO THE TEMPERATURE AT WHICH NUCLEATION OCCURS WHILE MAINTAINING SAID LAYERS IN A SUBSTANTIALLY INERT ATMOSPHERE; AND (D) THEREAFTER INCREASING THE TEMPERATURE OF SAID LAYERS FROM SAID TEMPERATURE AT WHICH NUCLEATION OCCURS, AT A RATE SUFFICIENT TO PRODUCE A MAXIMUM OF 10 CRYSTALS PER SQUARE CENTIMETER AND A RATE OF GROWTH OF THE CRYSTAL FRONT OF LESS THAN 0.1 MILLIMETER PER SECOND UNTIL CRYSTAL GROWTH IN SAID LAYER OF SEMICONDUCTOR IS COMPLETE.