US2723370A - Electrically semiconductive crystalline body - Google Patents

Electrically semiconductive crystalline body Download PDF

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Publication number
US2723370A
US2723370A US248308A US24830851A US2723370A US 2723370 A US2723370 A US 2723370A US 248308 A US248308 A US 248308A US 24830851 A US24830851 A US 24830851A US 2723370 A US2723370 A US 2723370A
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United States
Prior art keywords
globule
spike
contact
germanium
electrical
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Expired - Lifetime
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US248308A
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English (en)
Inventor
Bradshaw Stanley Edwin
Douglas Ronald Walter
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Hazeltine Research Inc
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Hazeltine Research Inc
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    • H10P95/00—
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D99/00—Subject matter not provided for in other groups of this subclass
    • H10W72/00—
    • H10W76/161—

Definitions

  • This invention relates to methods of producing electrically semiconductive crystalline bodies for use in electrical crystal-contact devices.
  • the invention is concerned in particular with electrical crystal-contact devices including semiconductive germanium elements prepared by a method including steps described in British Patent No. 635,385, which corresponds to copending U. S. application of Ronald W. Douglas, Serial No. 56,943, filed October 28,1948, and entitled Improvements in or Relating to Methods of Manufacturing Crystal Contact Devices, now abandoned.
  • the terms germanium and germanium element are intended to mean germanium of high purity with or without small quantities of added impurities.
  • globules prepared in this manner usually do not solidify in a perfectly spherical form but each has an outwardly projecting spike, the spike being formed from the germanium material which is last to solidify, and usually projects upwards when the globule is formed.
  • the globule After the globule is formed, it is preferably mounted on a metallic support and is then provided with a contact surface by removing part of the globule, for example by grinding.
  • a metallic contact member or electrical conductor When a metallic contact member or electrical conductor is brought into small-area contact with this surface, the contact exhibits at least one desirable electrical characteristic, that is, it has a high turnover voltage signifying that the current flow through the reverse impedance of the globule increases only slightly as an increasing negative voltage is applied across that impedance. In certain applications of the crystal-contact devices, it is desirable that the absolute magnitude of the turnover voltage should be as great as possible.
  • a method of producing an electrically semiconductive body for use in an electrical crystal-contact device comprises fusing in an inert atmosphere a suflicient quantity of electrically semiconductive crystalline material effective in its fused state by virtue of surface tension of the aforesaid material to produce a fluid globule, cooling the globule whereby there is formed thereon upon solidification an outwardly projecting spike having a higher concentration of impurities than the remainder of the aforesaid body, and removing the spike to form on the body, a contact surface lying in aplane substantially perpendicular to the direction of projection of the aforesaid spike for-engage ment with an electrical conductor.
  • Fig. 1 represents diagrammatically an electrically semiconductive crystalline body in the form of a globule
  • Fig. 2 is a view, partly in section, illustrating a stage in the manufacture of a crystalcontact device provided with a semiconducting crystalline element
  • Fig. 3 is a longitudinal sectional view of a completed crystal-contact device
  • Fig. 4 is a graph representing the electrical characteristic of a contact between an electrically semiconductive crystalline body and a metallic contact member in small-area contact with the body.
  • FIG. 1 there is represented an electrically semiconductive crystalline body in the form of a globule of high purity material such as germanium, this globule being produced by the method described in the above-identified British patent.
  • germanium such as germanium powder are fused in small holes or depressions in a carbon block to produce upon solidification globules having a diameter of about 1.6 millimeters and a mass of about 12 milligrams.
  • each globule 4 is mounted with its spike 1 projecting outwards on an electrical conductor or metal stub 5 which is provided with a conducting wire 6, the globule 4 first being nickel-plated and then being soldered in a recess 7 formed in the end of the stub 5.
  • the spiked part of the globule 4 is then ground away to form a contact surface 8 (see Fig. 1) which is preferably fiat, the surface lying in a plane 9 preferably being substantially perpendicular to the direction of projection of the spike 1 and positioned in the central portion or half of the length of the original globule 4 in the direction of projection of the spike 1, that is between the planes 2 and 3 shown in Fig. 1.
  • the contact surface 8 is then etched, and the stub is assembled to form part of the crystalcontact device represented in Fig. 3.
  • the germanium element formed from the globule 4 is arranged to coin a well-known manner to metal tubes 14 and 15 in which the stubs 5 and 11 are secured as by soldering.
  • British Patent No. 616,065 describes a particular method of forming a crystal-contact device of the type represented in Fig. 3 of the drawing.
  • the contact between the germanium element and the wire 10 exhibits an electrical characteristic of the form represented in Fig. 4, and it is found that the average value of the turnover voltage VT taken over a group of rectifiers manufactured by the method described above is considerably higher than the average value obtained for a group of rectifiers made up without reference to the position of the contact point in the original globule 4.
  • the concentration of impurities in the germanium is not uniform throughout the globule, owing to the fact that the impurities are more soluble in liquid germanium than solid germanium and the fact that the whole of the globule does not solidify simultaneously.
  • the concentration of impurities will be higher in the spiked part of the. globule than in the rest of the globule since this part is the last to solidify.
  • the concentration of the impurities at the contact point will vary with the position of the contact point in the globule.
  • the electrical characteristic of any particular contact will depend on the concentration of the impurities at the contact point and therefore on the position of the contact point in the globule.
  • the contact point or points is or are positioned in the central half of the length of the original globule'in the direction of projection of the spike 1, that is between the planes 2 and 3 shown in Fig. l.
  • greater uniformity in the electrical characteristics of the contacts maybe attained.
  • This may be conveniently achieved inaccordance with the invention by mounting the globule with the spike 1 projecting outwards and then removing the spiked part of the globule to form the contact surface.
  • the'average turnover voltage obtainable over a group of devices is'at a maximum when the contact points are positioned between the planes 2 and 3, and shows a comparatively small variation be tween these limits.
  • the present invention has utility not only in the manufacture of crystal diodes but also in the manufactureof electrical crystal-contact devices having two or more conductors in contact with the semiconducting element. While there has been described what is at present considered to be the preferred embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.
  • a method of producing an electrically semiconductive crystalline body for use in an electrical crystal-contact device comprising: fusing in an inert atmosphere a quantity of germanium not greater than 45 milligrams efiective in its fused state by virtue of surface tension of said germanium to produce a fluid globule; cooling said globule whereby there is formed thereon upon solidification an outwardly projecting spike having a higher concentration of impurities than the remainder of said body; securing an electrical conductor to a portion of said cooled globule adjacent said spike; cutting a slab from said body which includes said spike and which is substantially perpendicular to the direction of projection of said spike to form on said body a contact surface for engagement with an electrical conductor; and etching said contact surface.
  • a method of producing, an electrically semiconductive crystalline body for use in an electrical crystal-contact device comprising: fusing in an inert atmosphere a sufficient quantity of electrically semiconductive crystalline material effective in its fused state by virtue of surface tension of said material to produce a fluid globule; cooling said globule whereby there is formed thereon upon solidification an outwardly projecting spike having a higher concentration of impurities than the remainder of said body; and removing said spike to form on said body a contact surface lying in a plane substantially perpendicular to the direction of projection of said spike for engagement with an electrical conductor.
  • a method of producing an electrically semiconductive crystalline body for use in an electrical crystal-contact device comprising: fusing in an inert atmosphere a sufficient quantity of electrically semiconductive crystalline material effective in its fused state by virtue of surface tension of said material to produce a fluid globule; cooling said globule whereby there is formed thereon upon soliditication an outwardly projecting spike having a higher concentration of impurities than the remainder of said body; and removing said spike by grinding to approximately the central portion of said cooled globule to form on said body acontact surface lying in a plane substantially perpendicular to the direction of projection of said spike for engagement with an electrical conductor.
  • a method of producing an electrical crystal-contact device comprising: fusing in an inert atmosphere a sufficient quantity of electrically semiconductive crystalline material effective in its fused state by virtue of surface tension of said material to produce a fluid globule; cooling said globule whereby there is formed thereon upon solidification an outwardly projecting spike having a higher concentration of impurities than the remainder of said body; securing an electrical conductor to a portion of said cooled globule adjacent said spike; removing said spike 'by grinding to approximately the central portion of said cooled globule and in a plane to form a contact surface lying in a plane substantially perpendicular to the direction of projection of said spike for engagement with an electrical conductor; and bringing at least one electrical conductor into small-area contact with said contact sur-

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  • Crystals, And After-Treatments Of Crystals (AREA)
  • Die Bonding (AREA)
US248308A 1950-10-06 1951-09-26 Electrically semiconductive crystalline body Expired - Lifetime US2723370A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB24474/50A GB683248A (en) 1950-10-06 1950-10-06 Improvements in or relating to the manufacture of crystal contact devices

Publications (1)

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US2723370A true US2723370A (en) 1955-11-08

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US248308A Expired - Lifetime US2723370A (en) 1950-10-06 1951-09-26 Electrically semiconductive crystalline body

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US (1) US2723370A (index.php)
DE (1) DE865489C (index.php)
FR (1) FR1042521A (index.php)
GB (1) GB683248A (index.php)
NL (2) NL85899C (index.php)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2805369A (en) * 1952-08-27 1957-09-03 Philips Corp Semi-conductor electrode system
US2815474A (en) * 1957-01-25 1957-12-03 Pacific Semiconductors Inc Glass sealed semiconductor rectifier
US2866929A (en) * 1955-12-01 1958-12-30 Hughes Aircraft Co Junction-type-semiconductor devices and method of making the same
US2935386A (en) * 1956-01-03 1960-05-03 Clevite Corp Method of producing small semiconductor silicon crystals

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2891202A (en) * 1954-12-24 1959-06-16 Bendix Aviat Corp Semiconductor device
DE1084840B (de) * 1957-01-23 1960-07-07 Intermetall Verfahren zur Herstellung von kugelfoermigen Halbleiterkoerpern aus Silizium von Halbleiteranordnungen, z. B. Spitzen-Gleichrichtern oder Spitzen-Transistoren
DE1230912B (de) * 1960-06-09 1966-12-22 Siemens Ag Verfahren zum Herstellen einer Halbleiteranordnung
NL274757A (index.php) * 1961-02-15 1900-01-01

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419561A (en) * 1941-08-20 1947-04-29 Gen Electric Co Ltd Crystal contact of which one element is mainly silicon
GB635385A (en) * 1947-11-03 1950-04-05 Gen Electric Co Ltd Improvements in or relating to methods of manufacturing crystal contact devices
US2583008A (en) * 1945-12-29 1952-01-22 Bell Telephone Labor Inc Asymmetric electrical conducting device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419561A (en) * 1941-08-20 1947-04-29 Gen Electric Co Ltd Crystal contact of which one element is mainly silicon
US2583008A (en) * 1945-12-29 1952-01-22 Bell Telephone Labor Inc Asymmetric electrical conducting device
GB635385A (en) * 1947-11-03 1950-04-05 Gen Electric Co Ltd Improvements in or relating to methods of manufacturing crystal contact devices

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2805369A (en) * 1952-08-27 1957-09-03 Philips Corp Semi-conductor electrode system
US2866929A (en) * 1955-12-01 1958-12-30 Hughes Aircraft Co Junction-type-semiconductor devices and method of making the same
US2935386A (en) * 1956-01-03 1960-05-03 Clevite Corp Method of producing small semiconductor silicon crystals
US2815474A (en) * 1957-01-25 1957-12-03 Pacific Semiconductors Inc Glass sealed semiconductor rectifier

Also Published As

Publication number Publication date
NL164481B (nl)
DE865489C (de) 1953-02-02
FR1042521A (fr) 1953-11-02
GB683248A (en) 1952-11-26
NL85899C (index.php)

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