Abstract:
Refractory tubings, either in amorphous, polycrystalline or single crystal form, are made by moving a preformed tubing of a refractory material and a heated zone relative to each other, the heating zone providing sufficient heat to melt through the tubing and form a molten ring which is continuously advanced through the tubing. The heat source may be located externally or internally of the tubing wall or in both positions. The tubings may be formed as single crystals by using appropriate seeds; and by controlling the rate of movement of the tubing sections on either side of the molten ring the wall thickness and diameter of the final tubing may be adjusted.
Abstract:
Improvements in apparatus for zone refining polycrystalline semiconductor rods to produce monocrystalline semiconductor rods are disclosed. In the apparatus, an inductive heating chamber is employed which has a longitudinal dimension independent of the length of the polycrystalline semiconductor rod to be processed. The longitudinal dimension of the induction heating chamber is limited only by considerations of the space required for the RF induction heating coil and related apparatus which must be mounted within the chamber, the viewing space required for the operator to observe the zone refining process, and the heating effect on the structures above and below the chamber. First and second gas tight bellows are provided which, respectively, surround the rod holder and the seed holder. One end of each of the first and second bellows is releasably and sealingly attached to the induction heating chamber, while the other end of each of the first and second bellows is attached to the base of the rod holder or seed holder, respectively. These bellows expand and collapse with the relative movement of the rod holder and seed holder with respect to the induction heating chamber. Moreover, with the rod holder displaced from the induction heating chamber, the first bellows may be detached from the chamber and collapsed to facilitate mounting a polycrystalline semiconductor rod to be refined in the rod holder, and when the refining process is complete and the seed holder is displaced from the chamber, the second bellows can be detached from the chamber and collapsed to facilitate the removal of the refined monocrystalline rod from the seedholder. In order to protect the lower most bellows from molten semiconductor, a plurality of telescoping metallic cylinders are positioned within the bellows and concentric therewith.
Abstract:
A method for preparing single crystals of lanthanum hexaboride (LaB.sub.6) by arc melting a rod of compacted LaB.sub.6 powder. The method is especially suitable for preparing single crystal LaB.sub.6 cathodes for use in scanning electron microscopes (SEM) and scanning transmission electron microscopes (STEM).
Abstract:
A method of producing monocrystalline semiconductor material in web form from a source of polycrystalline semiconductor material. The source material is heated to form a molten zone on the end thereof, which is contacted by a thermal profile shaping member formed from the same type of semiconductor material as the semiconductor material to be produced. A monocrystalline seed crystal of the shape of the web desired then contacts the molten end of the source material near the shaping member and is withdrawn therefrom as monocrystalline semiconductor material forms on the end thereof.
Abstract:
An orthoferrite single crystal is grown by the floating zone method with the growth direction of the crystal perpendicular to the easy axis of magnetic anisotropy by using a starting seed crystal whose easy axis is disposed perpendicular to the growth direction. The thus produced crystal is then cut into thin platelets in which the plane surfaces thereof are perpendicular to the easy axis of magnetic anisotropy.
Abstract:
A method of zonal melting of materials without a crucible comprises the following steps: placing a layer of unrefined material upon the circumferential surface of a previously molten ingot of refined material; and zonal melting of the layer and ingot together in the course of which a floating zone is embedded to a predetermined depth of the initial ingot, thereby increasing the circumferential diameter of the ingot.
Abstract:
Method of growing rod-shaped monocrystals by floating zone melting includes adjusting the orientation of the seed crystal in its holder so that a main crystal axis thereof, which extends substantially in the longitudinal direction thereof, is inclined at an angle between 0.5* and 5* to the direction in which the rotary axis of the seed holder extends, and, at the start of the relative movement between the induction heating coil and the rod for passing a molten zone axially through the rod, the rod holder and the crystal holder are moved relatively away from one another so as to increase the spacing therebetween and form a bottleneckshaped constriction at the end of the rod to which the seed crystal is fused.
Abstract:
Apparatus for crucible-free zone melting a crystalline rod comprising a melting zone chamber having a substantially horizontal wall formed with an opening therein, a slide member adjacent the horizontal wall outside of the chamber for sealingly covering the opening, a pair of spaced holders mounted in the chamber for vertically end supporting a crystalline rod between them, means for relatively displacing the end holders toward one another, an annular heating device surrounding and spaced from the rod and adapted to form a molten zone in the rod wherefrom a portion of the rod recrystallizes, means for displacing the slide member and the rod holder for the recrystallizing rod portion in a substantially horizontal direction transverse to the axis of the rod, and means for rotating at least the rod holder for the recrystallizing rod portion comprising a drive shaft extending vacuum-tightly through an opening in the slide member and the opening in the wall and connected to the rotatable holder in the chamber.
Abstract:
PROCESS OF ZONE MELTING A SEMICONDUCTOR ROD HAVING UNDER PROCESS, A RECRYSTALLIZED PORTION AND SUPPLY PORTION TO BE RECRYSTALLIZED, EACH SEPARATED FROM THE OTHER BY A MOLTEN ZONE, INCLUDES SUPPORTING THE ROD SUBSTANTIALLY VERTICALLY BY FIRST AND SECOND HOLDERS RESPECTIVELY LOCATED AT THE FREE ENDS OF THE SUPPLY ROD PORTION AND THE RECRYSTALLIZED ROD PORTION, FORMING THE MOLTEN ZONE IN THE ROD WITH AN ANNULAR HEATING DEVICE SPACED FROM AND SURROUNDING THE ROD, RELATIVELY MOVING THE ROD AND THE HEATING DEVICE IN A SUBSTANTIALLY VERTICAL DIRECTION SO AS TO PASS THE MOLTEN ZONE ALONG THE ROD, ROTATING AT LEAST ONE OF THE END HOLDERS ABOUT THE SUBSTANTIALLY VERTICAL AXIS OF THE ROD PORTION AT THE FREE END OF WHICH THE END HOLDER IS LOCATED, RELATIVELY MOVING THE END HOLDER TOWARDS ONE ANOTHER AND LATERALLY AWAY FROM ONE ANOTHER AT PREDETERMINED SPEEDS SO AS TO INCREASE THE THICKNESS OF THE RECRYSTALLIZED ROD PORTION IN A DIRECTION RADIALLY OUTWARDLY TO THE ANNULAR HEATING DEVICE AND ROTATING THE SUPPLY ROD PORTION ABOUT AN AXIS ECCENTRIC TO THE SUBSTANTIALLY VERTICAL AXIS OF THE SUPPLY ROD PORTION. APPARATUS FOR CARRYING OUT THE FOREGOING METHOD INCLUDES SUBSTANTIALLY VERTICAL SPACED END HOLDERS SUPPORTING BETWEEN THEM A VERTICALLY EXTENDING SEMICONDUCTOR ROD HAVING A RECRYSTALLIZED PORTION AND A SUPPLY PORTION TO BE RECRYSTALLIZED DIVIDED BY A MOLTEN ZONE, MEANS FOR RELATIVELY DISPLACING THE END HOLDERS TOWARD ONE ANOTHER, AN ANNULAR HEATING DEVICE SURROUNDING AND SPACED FROM THE ROD AND ADAPTED TO FORM THE MOLTEN ZONE IN THE ROD, MEANS FOR DISPLACING THE HEATING DEVICE ALONG THE ROD SO AS TO PASS THE MOLTEN ZONE ALONG THE ROD, MEANS FOR ROTATING AT LEAST ONE OF THE END HOLDERS ABOUT ITS SUBSTANTIALLY VERTICAL AXIS, MEANS FOR DISPLACING ONE OF THE END HOLDERS IN A DIRECTION TRANSVERSE TO THE AXIS THEREOF SO THAT THE RECRYSTALLIZED ROD PORTION IS FORMED WITH A SPECIFIC DIAMETER EXTENDING IN DIRECTION TOWARD THE ANNULAR HEATING DEVICE, AND MEANS FOR ROTATING THE SUPPLY ROD PORTION ABOUT AN AXIS ECCENTRIC TO THE AXIS OF THE SUPPLY ROD PORTION.
Abstract:
A method and apparatus for controlling a heated bath of molten material to obtain controlled solidification, wherein the molten bath is kept in constant rotational movement relative to the solid portion of the material being treated and the mechanical action due to the viscous friction which develops in the bath is detected and thereby controlled, said method being applicable to the floating zone method and the Czochralsky crystal drawing method and being capable of producing ingots of high dimensional regularity.