Crystal growing apparatus

Claim 1

APPARATUS FOR RAPIDLY GROWING A MONOCRYSTALLINE WIRE OF SEMICONDUCTIVE MATERIAL FROM A MELT OF THE SAME SAID APPARATUS COMPRISING: 8A) A CRUCIBLE OF INERT REFRACTORY MATERIAL COMPRISING A SOLID BOTTOM SUPPORTING PORTION WITH AN INTEGRAL UPWARDLY EXTENDING SIDE WALL PORTION FORMING AN OPEN TOP RECEPTACLE SUITABLE FOR CONFINING A MELT OF SEMICONDUCTIVE MATERIAL; (B) MEANS FOR INTRODUCING SEMICONDUCTIVE MATERIAL TO BE MELTED INTO SAID CRUCIBLE; (C) MEANS FOR HEATING SEMICONDUCTOR MATERIAL INTRODUCED INTO SAID CRUCIBLE TO A TEMPERATURE AT LEAST AS HIGH AS THE MELTING TEMPERATURE OF THE SEMICONDUCTIVE MATERIAL; (D) A TOP COVER OF INERT REFRACTORY MATERIAL FOR SAID CRUCIBLE HAVING A PERIPHERAL PORTION THEREOF ABUTTING THE SIDE WALL OF SAID CRUCIBLE NEAR THE UPPERMOST EXTREMITY OF SAID SIDE WALL, SAID PERIPHERAL PORTION INCLUDING AN ANNULAR UPPER SURFACE, SAID COVER HAVING AN INVERTED FRUSTOCONICAL-SHAPE CENTRAL PORTION DEPENDING FROM SAID PERIPHERAL PORTION AND HAVING THE INNERMOST PART THEREOF ADAPTED TO BE SUBMERGED UNDER THE SURFACE OF A MELT WITHIN SAID CRUCIBLE, THE CENTERMOST PORTION OF SAID COVER COMPRISING AN ANNULAR LIP PROJECTING UPWARDLY FROM THE INNERMOST PART OF SAID FRUSTOCONICAL-SHAPE CENTRAL PORTION AND ADAPTED TO EXTEND TO AT LEAST THE TOP SURFACE OF A MELT WITHIN SAID CRUCIBLE, AND SAID ANNULAR LIP DEFINING A SMALL DIAMETER CENTRAL APERTURE THROUGH WHICH A CRYSTAL CAN BE WITHDRAWN CONTINUOUSLY FROM A REALTIVELY SMALL CONVEXED PART OF THE TOP SURFACE OF A MELT WITHIN SAID CRUCIBLE; (E) A COOLING SHIELD OF HIGH THERMAL CONDUCTIVITY METAL HAVING A PERIPHERAL PORTION THEREOF ENGAGING SAID ANNULAR UPPER SURFACE OF SAID COVER, SAID SHIELD HAVING A CONTINUOUS PASSAGE THEREIN FOR FLOW OF A COOLING MEDIUM, AND SAID SHIELD HAVING AN INVERTED FRUSTOCONICAL-SHAPE CENTRAL PORTION SPACED FROM SAID COVER AND DEPENDING FROM THE PERIPHERAL PORTION OF SAID SHIELD, THE CENTRAL PORTION OF SAID SHIELD HAVING A CYCLINDRICAL APERTURE THEREIN THAT IS CLOSELY SPACED COAXIAL RELATIONSHIP TO THE CENTRAL APERTURE OF SAID COVER, WHEREBY A HIGH THERMAL GRADIENT IS ESTABLISHED ADJACENT THE TOP OF THE ANNULAR LIP OF SAID COVER WITHOUT SUBJECTING THE MAJOR SURFACE OF A MELT WITHIN SAID CRUCIBLE TO DELETERIOUS COOLING; (F) MEANS FOR CONTINUOUSLY WITHDRAWING A GROWN CRYSTAL FROM THE TOP SURFACE OF A MELT WITHIN THE ANNUCLEAR LIP OF SAID COVER THROUGH THE APERTURES IN SAID COVER AND SAID SHIELD.