Leybold Aktiengesellschaft

Leybold-heraeus Gmbh & Co. Kg

Dieter Drechsel

Karl Jericho

Uwe Reimpell

Joachim Floymayr

A lock valve disposed between a pulling pot and a lock chamber is opened at the start of the pulling process and thereby uncovers a lock entrance for the crystal that is to be pulled, and together with a gasket closes the lock entrance after the end of the pulling process and thereby hermetically separates the pulling pot from the lock chamber. The gasket (9) is protected during the pulling of the crystal by a guard (15, 16) against the thermal radiation of the hot crystal.

Apparatus for crystal pulling

A method and an apparatus are proposed for pulling crystals from the melt. The recharging of the melt (4) is performed such that the crucible (3) is raised and lowered with respect to the crystal pulling system while keeping the position of the melt surface (25) constant with respect to the crystal pulling system. In particular it is proposed that, during a first time interval (34) the amount of recharge (37) per unit time be greater than the average amount of recharge (38, 39) per unit time that would be necessary in order to make up for the consumption of material by the growing crystal (5), that during a second time interval (45) the amount of recharge (46) per unit time be less than the average recharge amount per unit time that would be necessary in order to make up for the consumption of material by the growing crystal, that during the first time interval the crucible (3) be lowered to keep the melt surface constant with respect to the crystal pulling apparatus, that during the second time interval the crucible (3) be raised to keep the melt surface constant with respect to the crystal pulling apparatus. By the invention, erosion ring grooves on the inside wall of the crucible are prevented and thus the useful life of the crucible is considerably lengthened. The method according to the invention can be practiced on existing apparatus.

Crystal pulling method and apparatus for the practice thereof

A pulling shaft carries a seed crystal holder and moves it vertically to pull a crystal upward from a melt in a crucible. The pulling shaft is rotated by a drive to cause the crystal to rotate while being pulled. A slippage device is provided to permit a difference between rotational speeds of the pulling shaft and the seed crystal. The slippage device may be incorporated in a crystal holder having an inner holder fixed to the seed crystal, an outer holder fixed to the shaft, and a friction bearing therebetween which prevents undue torsional stress from being transmitted to the crystal.

Device for pulling crystals

Apparatus includes a crucible, a cover with an opening over the crucible, a pulling element for pulling monocrystal from melt in the crucible, and first and second heating elements. The first element is a substantially flat radiaent heat source below the crucible and the second element is a pot shaped, comprising a flat heat source above the melt and a cylindrical heat source about the crucible. A ring having holes therethrough is inserted in the crucible to quiet the melt, a filler funnel emptying material to be molten outside of the ring while the monocrystal is pulled from inside the ring.

Apparatus for pulling monocrystals

In an apparatus for the continuous feeding of material to a melting crucible in the pulling of monocrystals in a vacuum tank, a first container (3) is provided which is provided with an internal lining (4) adapted to the container shape and having a funnel-shaped section (4') and a cylindrical outlet (4'') adjoining the latter, the outlet (4'') being displaceable through a lock valve (10) into the connecting pipe (11) of a second container (12) which in turn, through an outlet tube (18) with elbow (19) brought through the wall of the vacuum tank, leads into the area above the melting crucible. The two containers (3, 12) are for that purpose coupled with the hydraulic cylinder (28) of a linear actuator by which the distance between the two containers (3, 12) can be varied.

Apparatus for the continuous feeding of material to be melted

Apparatus for producing monocrystals by potless zone melting, in which the monocrystal, setting out from a seed crystal, passes through a neck and a transitional zone into the main part of the monocrystal. A chamber is provided for the formation of a vacuum or a protective gas atmosphere plus a heating device for the production of the melting heat, driving means for the mechanical movements necessary for the crystal formation, a mounting for the seed crystal, and a supporting device which is applicable to the monocrystal beyond the neck, and a plurality of gripping bodies distributed about the circumference and applicable to the monocrystal radially on its substantially cylindrical surface the gripping bodies are disposed such that they first perform a radial approach to the monocrystal until a virtually force-free contact is made therewith, adapting themselves to the surface geometry and position of the monocrystal, whereupon the gripping force is increased and the gripping bodies are locked.

Growing community of inventors

Bruchkoebel, Germany

Dieter Drechsel