US 3793984 A
An apparatus for producing semiconductor tubes by means of depositing semiconductor material from a gaseous atmosphere onto a heated receiver body, the receiver body consists of a concentric assembly of inner and outer conductive members connected at one end by means of cooperating screw threads on the two members, and a conical end cap member covering the end of the assembly and forming a smooth continuous surface with the exterior of the outer member.
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Description (OCR text may contain errors)
United States Patent [191 Kasper et a1.
[ 1 Feb. 26, 1974 APPARATUS FOR THE PRODUCTION OF CLOSED END TUBES OF SEMICONDUCTOR MATERIAL Inventors: Andreas Kasper,
Garching-I-Iochbrueck; Wolfgang Dietze, Munich, both of Germany Siemens Aktiengesellschaft, Berlin and Munich, Germany Filed: Nov. 13, 1972 Appl. No.2 306,011
Foreign Application Priority Data Nov. 24, 1971 Germany 2158257 US. Cl 118/48, 219/275, 264/81, 338/217 Int. Cl. C23c 13/08 Field of Search 1 18/48-49.5; 117/106l07.2; 264/81; 425/447; 219/271, 275; 338/217, 218
References Cited UNITED STATES PATENTS 2/1942 I-lanawalt et al. 219/275 UX 2,355,343 8/1944 Von Zeerleder et al..... 219/275 UX 2,858,403 10/1958 Butler, Jr. 219/275 UX 2,955,566 10/1960 Campbell et al.... 118/48 3,139,363 6/1964 Baldrey 264/81 3,451,772 6/1969 McCabe et a1. 264/81 3,717,439 2/1973 Sakai 338/217 X FOREIGN PATENTS OR APPLICATIONS 450,959 7/1936 Great Britain 219/355 364,700 11/1938 Italy 338/217 Primary ExaminerMorris Kaplan Attorney, Agent, or FirmI-Ii1l, Sherman, Meroni, Gross & Simpson [5 7] ABSTRACT An apparatus for producing semiconductor tubes by means of dep ositing semiconductor maie'fi'affiafifa gaseous atmosphere onto a heated receiver body, the receiver body consists of a concentric assembly of inner and outer conductive members connected at one end by means of cooperating screw threads on the two members, and a conical end cap member covering the end of the assembly and forming a smooth continuous surface with the exterior of the outer member.
5 Claims, 1 Drawing Figure APPARATUS FOR THE PRODUCTION OF CLOSED END TUBES OF SEMICONDUCTOR MATERIAL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to apparatus used in the production of closed end tubes made of semiconductor material by depositing semiconductor material from a gaseous atmosphere onto a receiver body, and more particularly to an improved structure for such a re ceiver body.
2. The Prior Art Apparatus used in the production of closed end tubes by depositing the material from a gaseous atmosphere has been described in co-pending application Ser. No. 253,629 filed on May 15, 1972, now U.S. Pat. No. 3,747,559 by Wolfgang Dietze for Apparatus for Production of a Closed Tube of Semiconductor Material. As described in the Dietze application, a receiver body is provided to receive a coating of the semiconductor material. The receiver body is made up of a rod and a concentric surrounding tube, the tube and rod being interconnected at one end by means of cooperating screw threads or the like. Electrical current is passed through the rod and tube to heat them to the proper temperature, and the resistance of the circuit is adjusted by modifying the distance which the rod is screwed into the tube, which determines the contact area. The end of the tube is covered by a cap member. The Dietze application describes several varieties of cap member, however, all of the cap members of the Dietze application form, with the tube member, a right circular cylinder, having an end surface normal to the axis of the receiver body. It has been found that heating of the receiver body is not uniform over its entire surface with such an arrangement, with the result that the deposited semiconductor material hasa non-uniform thickness. Accordingly, it is desirable to provide a receiver body in which the heating of the receiver body is uniform.
SUMMARY OF THE INVENTION It is a principal object of the present invention to provide a cap structure for a heated receiver body adapted for receiving a deposited layer of semiconducting material, which provides for uniformity in heating over the entire surface of the body.
Another object of the present invention is to provide such a cap structure in which grinding of the receiver body after assembly to obtain a smooth, continuous surface between the cap member and the exterior of the tube can be reduced to a minimum.
A further object of the present invention is to provide a receiver body which has great mechanical stability.
These and other objects and advantages of the present invention will become manifest upon an inspection of the following description and the accompanying drawings.
In one embodiment of the present invention there is provided an end cap, for closing the end surface of an axially symmetric receiver body, having a convex, conical end surface coaxial with the axis of the receiver body, the edges of said convex end surface being rounded to form a smooth, continuous surface between the cap member and the exterior of the receiver body.
BRIEF DESCRIPTION OF THE DRAWINGS Reference will be made to the accompanying drawing which is a vertical cross-section through a receiver body incorporating an illustrative embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, an axially symmetric receiver body is illustrated, the plane of the crosssection of the drawing passing through the axis of the body. The body includes a central rod 10 and an outer tube 11 which surrounds the rod 10. The tube 11 has an inwardly extending flange at its end, and the rod 10 and the tube 11 are interconnected by means of cooperating threads 12 disposed on the end of the rod 11, and on the inner surface of the inwardly extending flange. The area of contact between the rod 10 and the tube 11 may be varied by relative rotation between the rod 10 and the tube 11.
A central bore 14 is provided in the end of the rod 10, and the stem of a cap member 13 is disposed in the bore and threadably connected therewith. One set of the threads is provided on the external surface of the stem of the cap member 13, and a set of cooperating threads is provided within the bore 14.
The inner surface of the cap member 13 lies closely adjacent the upper end of the tube 11, and the outer surface is convexly conical in shape, being thickest near the center 15 and thinest near the peripheral edge 16. After the cap is assembled in cooperation with the rod 10 and the tube 1 l, the sharp corner formed at the outer edge 16 of the cap 13 is removed by grinding, forming the shape indicated by the dashed lines 17, and producing thereby a smooth continuous surface betweenthe conical surface of the cap 13 and the circular cylindrical outer surface of the tube 11.
It has been found that the provision of the conical outer surface facilitates uniform temperature distribution throughout the receiver body, and enhances the deposition of a uniform thickness of semiconducting material thereon. In addition it provides a cap structure of greater mechanical stability, as compared with a thin flat cap structure. Because the outer edge 16 is thin, very little material is removed during grinding the outer edge to produce the desired smooth, continuous surface of the completed receiver body.
The cap 13 is made of the same material as the rod 10 and the tube 11, in order to enhance uniform heating over the entire surface of the receiver body. Preferably, the material is vitreous carbon, spectral carbon, or pyrolytic graphite.
We claim as our invention:
1. In an apparatus for producing closed end tubes of semiconductor material wherein is provided a vacuum deposition chamber including a gaseous supply of such semiconductor material and electrical means to heat and mount a heated receiver body upon which said semiconductor material is deposited, the improvement wherein said receiver body comprises a central rod formed of electrically conductive material a surrounding tube formed of electrically conductive material, and having an end in electrical contact with an end of said tube; and an electrically conductive cap member for covering said end of said tube, said cap member having a convex outer surface including a curved edge na] dimension of said tube, and said cap member has an annular inner surface adapted to lie closely adjacent the end surface of said tube.
5. The cap member of claim 1, wherein said central rod is provided with a central threaded bore, and said cap member has a stem threadably received in said bore.