US2861230A - Calorized point contact electrode for semiconductor devices - Google Patents

Calorized point contact electrode for semiconductor devices Download PDF

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Publication number
US2861230A
US2861230A US394001A US39400153A US2861230A US 2861230 A US2861230 A US 2861230A US 394001 A US394001 A US 394001A US 39400153 A US39400153 A US 39400153A US 2861230 A US2861230 A US 2861230A
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Prior art keywords
point contact
electrode
calorized
contact electrode
type
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US394001A
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English (en)
Inventor
Theodore E Leloup
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General Electric Co
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General Electric Co
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Publication date
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Priority to US394001A priority Critical patent/US2861230A/en
Priority to GB33610/54A priority patent/GB798213A/en
Priority to FR1114651D priority patent/FR1114651A/fr
Application granted granted Critical
Publication of US2861230A publication Critical patent/US2861230A/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
    • H10P95/00—Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass

Definitions

  • P-type semiconductors such as prepared germanium and silicon are normally classified as either positive (P-type) or negative (N-type) depending primarily on the type and sign of their main electrical conduction carriers.
  • N-type semiconductors the excess conduction carriers are electron vacancies or holes produced by the movement of electrons in the valence band
  • the excess conduction carriers are electrons moving in the conduction band.
  • the direction of rectification as well as the polarity of various voltage effects is diflerent in semiconductors of the two types.
  • Whether a particular semiconductor is of the P-type or the N-type depends primarily on the type of impurity present in the material. Some impurities called donors, such as antimony, phosphorus, and arsenic furnish free additional electrons to the semiconductors, such as germanium and silicon, and produce an N-type material. Other impurities called acceptors, such as aluminum, gallium, indium, and zinc tend to absorb electrons leaving electron vacancies or holes in the material to produce a so-called P-type semiconductor. Only very small amounts of these impurities are required to produce marked electrical effects of one type or the other.
  • Point contact semiconductor units are those in which a semiconductor body, such as an N-type germanium, has joined to the surface thereof, a whisker or point contact electrode of a metal such as tungsten, platinum, and the like.
  • a semiconductor body such as an N-type germanium
  • whisker or point contact electrode of a metal such as tungsten, platinum, and the like.
  • An object of my invention is to provide a point contact electrode for semiconductor devices which is characterized by reduced forward voltage.
  • Another object of my invention is to provide a point contact electrode for semiconductor devices which has advantages of the P-N junction type device while retaining the. advantages of the. point contact type.
  • Another object of my invention is to provide semiconductor devices having improved characteristics.
  • my invention comprises a semiconductor device of the Whisker or point contact type in which the whisker or point contact electrode is calorized by heating in a mixture of aluminum and, alumina powders and preferably thereafter subjected to a separate non-oxidizing heat treatment.
  • body 1 of my semiconductor device'is typically of N-type germanium is, preferably mono-crystalline in nature, and is purified to have a resistivity over 2 ohm-centimeters.
  • Body 1 may be conveniently extractcd from a monocrystalline germanium ingot grown by seed crystal withdrawal from a. melt of germanium having a trace, less than 0.05%, of a donor impurity which makes the body of N-type conductivity.
  • a second whisker or point contact electrode 4 is welded to the surface of body 1 as shown by passing therethrough a short pulse of current sufficient to fuse the tip of electrode 4 to body 1.
  • the crux of my invention lies in the metallurgical structure of electrode 4 and the treatment to which it is subjected.
  • Electrode 4 is typically 0.004 inch in diameter although it may range from about 0.003 inch to 0.006 inch in diameter. It may be basically platinum, tungsten, or any other physically adaptable metal. The electrodes used in the examples below are of platinum.
  • the platinum wire is subjected to a calorizing treatment consisting of two steps, a direct calorizing treatment followed by a diffusion treatment.
  • the wire is placed first in a mixture of aluminum power and alumina (A1 0 powder consisting of from 10 to 20 percent aluminum with the rest alumina and then heated to from 400 C. to 600 C. for from four to six hours in a reducing or non-oxidizing atmosphere.
  • This heat treatment is of a time-temperature nature, the time of treatment bein'g longer at the lowest temperatures and shorter at the higher temperatures.
  • the aluminum impregnates the surface of the wire to form there a platinum-aluminum alloy.
  • the latter is preferably subjected to a. diffusion treatment in which the wire is heated in a reducing or nonoxidizing atmosphere for from four to six hours at a temperature of from 800 C. to 1000 C. during which process the aluminum passes through, and alloys with the entire electrode material.
  • the diffusion step is also of a time-temperature nature.
  • the platinum wire is next cut into suitable lengths for electrode use.
  • all electrodes were ground to an angle of about 20. Exactly similar angles were obtained by fixing the electrodes to a glass plate with wax and then grinding the plate and wire to the indicated angle. In actual present practice the exact angle of the contact is not critical.
  • the point contact electrodes of my invention may be cut to size and pointed or otherwise. formed prior to the calorizing treatment.
  • a pulse of 40 volts for about one-quarter second with a load resistance of 50 ohms is satisfactory with the electrodes of the above size range.
  • germanium diodes made by my process were tested with the following results as: compared to an exactly similar diode in which the contact electrode was not calorized.
  • the method of making a point contact electrode for a semiconductor device which comprises calorizing wire of material chosen from the group consisting of platinum and tungsten in a mixture of from 10 percent to 20 percent by weight aluminum powder and 80 percent to 90 percent alumina powder at a temperature from 400 C.
  • a point contact type semiconductor electrical device comprising an N type germanium body, a first electrode attached to one surface of said body and a point contact electrode welded to another surface of said body, said second electrode consisting of an alloy of aluminum with a material chosen from the group consisting of platinum and tungsten.
  • a point contact type semiconductor electrical device comprising an N type germanium body, a first electrode attached to one surface of said body and a point contact electrode Welded to another surface of said body, said second electrode consisting of an alloy of aluminum with platinum.
  • a point contact type semiconductor electrical de vice comprising an N" type germanium body, a first electrode attached to one surface of said body and a point contact electrode welded to anothersurface of said body, said second electrode consisting of an alloy of 4.
  • a semiconductor electrical device comprising a semiconductor body, a first electrode attached to one surface of said body and a second point contact electrode attached to another surface of said body, said second electrode consisting of an alloy of aluminum with a metal to 600 C. for a period of four to six hours in a nonoxidizing atmosphere, removing the wire from said mixture of aluminum powder and alumina and heating said wire at a temperature from 800 C. to 1000 C. for a period of four to six hours in a non-oxidizing atmosphere.
  • the method of making a point contact electrode for a semiconductor device which comprises calorizing platinum wire in a mixture of from 10 percent to 20 percent by weight aluminum powder and percent to percent alumina powder at a temperature from 400 C. to 600 C. for a period of four to six hours in a non-oxidizing atmosphere, removing the wire from said mixture of aluminum powder and alumina and heating said wire at a temperature from 800 C. to 1000 C. for a period of four to six hours in a non-oxidizing atmosphere.
  • the method of making a point contact electrode for a semiconductor device which comprises calorizing tungsten wire in a mixture of from 10 percent to 20 percent by weight aluminum powder and 80 percent to 90'percent alumina powder at a temperature from 400 C. to 600 C. for a period of four to six hours in a non-oxidizing atmosphere removing the wire from said mixture of aluminum powder and alumina and heating said wire at a temperature from 800 C. to 1000 C. for a period of four to six hours in a non-oxidizing atmosphere.
  • a semiconductor electrical device comprising a semiconductor body, a first electrode attached to one surface of said body and a second point contact electrode welded to another surface of said body, said second electrode consisting of an alloy of aluminum with a material chosen from the group consisting of platinum and tungsten.
  • a semiconductor electrical device comprising a semiconductor body, a first electrode attached to one surface of said body and a second point contact electrode welded to another surface of said body, said second electrode consisting of a calorized wire, said wire being formed of a material chosen from the group consisting of platinum and tungsten and calorized in a mixture of from 10% to 20% by weight of aluminum powder and 80% to 90% of alumina powder at a temperature from 400 to 600 C. for a period of four to six hours in a non-oxidizing atmosphere.
  • a semiconductor electrical device comprising a semiconductor body, a first electrode attached to one surface of said body and a second point contact electrode welded to another surface of said body, said second electrode consisting of a calorized wire, said wire being formed of a material chosen from the group consisting of platinum and tungsten and calorized in a mixture of from 10% to 20% by weight of aluminum powder and 80% to 90% alumina powder at a temperature from 400 to 600 C. for a period of four to six hours in a non-oxidizing atmosphere and then heated at a temperature from 800 to 1000 C. removed from said alumina and aluminum powder for a period of four to six hours in a non-oxidizing atmosphere.

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US394001A 1953-11-24 1953-11-24 Calorized point contact electrode for semiconductor devices Expired - Lifetime US2861230A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US394001A US2861230A (en) 1953-11-24 1953-11-24 Calorized point contact electrode for semiconductor devices
GB33610/54A GB798213A (en) 1953-11-24 1954-11-19 Improvements relating to semiconductor devices
FR1114651D FR1114651A (fr) 1953-11-24 1954-11-24 Dispositif semi-conducteur à contact

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US394001A US2861230A (en) 1953-11-24 1953-11-24 Calorized point contact electrode for semiconductor devices

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US2861230A true US2861230A (en) 1958-11-18

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FR (1) FR1114651A (fr)
GB (1) GB798213A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2933662A (en) * 1954-01-14 1960-04-19 Westinghouse Electric Corp Semiconductor rectifier device
US3150297A (en) * 1958-04-24 1964-09-22 Clevite Corp Lead wire connection for semiconductor device
US3196328A (en) * 1962-02-28 1965-07-20 Hughes Aircraft Co Low noise microwave mixer diode
US3211594A (en) * 1961-12-19 1965-10-12 Hughes Aircraft Co Semiconductor device manufacture
US3231421A (en) * 1962-06-29 1966-01-25 Bell Telephone Labor Inc Semiconductor contact
US3239376A (en) * 1962-06-29 1966-03-08 Bell Telephone Labor Inc Electrodes to semiconductor wafers

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1091057A (en) * 1913-03-12 1914-03-24 Gen Electric Process of treating metals.
US2319364A (en) * 1938-05-06 1943-05-18 Ziegs Paul Electrical heating conductor and method of producing same
US2402839A (en) * 1941-03-27 1946-06-25 Bell Telephone Labor Inc Electrical translating device utilizing silicon

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1091057A (en) * 1913-03-12 1914-03-24 Gen Electric Process of treating metals.
US2319364A (en) * 1938-05-06 1943-05-18 Ziegs Paul Electrical heating conductor and method of producing same
US2402839A (en) * 1941-03-27 1946-06-25 Bell Telephone Labor Inc Electrical translating device utilizing silicon

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2933662A (en) * 1954-01-14 1960-04-19 Westinghouse Electric Corp Semiconductor rectifier device
US3150297A (en) * 1958-04-24 1964-09-22 Clevite Corp Lead wire connection for semiconductor device
US3211594A (en) * 1961-12-19 1965-10-12 Hughes Aircraft Co Semiconductor device manufacture
US3196328A (en) * 1962-02-28 1965-07-20 Hughes Aircraft Co Low noise microwave mixer diode
US3231421A (en) * 1962-06-29 1966-01-25 Bell Telephone Labor Inc Semiconductor contact
US3239376A (en) * 1962-06-29 1966-03-08 Bell Telephone Labor Inc Electrodes to semiconductor wafers

Also Published As

Publication number Publication date
FR1114651A (fr) 1956-04-16
GB798213A (en) 1958-07-16

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