US2464066A - Method of reducing the leakage current in selenium rectifiers - Google Patents

Method of reducing the leakage current in selenium rectifiers Download PDF

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Publication number
US2464066A
US2464066A US613326A US61332645A US2464066A US 2464066 A US2464066 A US 2464066A US 613326 A US613326 A US 613326A US 61332645 A US61332645 A US 61332645A US 2464066 A US2464066 A US 2464066A
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Prior art keywords
rectifier
current
temperature
treatment
rectifiers
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Expired - Lifetime
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US613326A
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English (en)
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Addink Nicolaas Willem Hendrik
Boucher Charles Louis
Kramer Jan
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D48/00—Individual devices not covered by groups H10D1/00 - H10D44/00
    • H10D48/01—Manufacture or treatment
    • H10D48/04—Manufacture or treatment of devices having bodies comprising selenium or tellurium in uncombined form
    • H10D48/048—Treatment of the complete device, e.g. by electroforming to form a barrier
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D48/00—Individual devices not covered by groups H10D1/00 - H10D44/00
    • H10D48/01—Manufacture or treatment
    • H10D48/04—Manufacture or treatment of devices having bodies comprising selenium or tellurium in uncombined form

Definitions

  • the invention relates to a method of reducing the leakage current in selenium rectifiers.
  • the invention has for its object to provide means by which, relatively to the known method, the leakage current is still further reduced or in other words whereby it is possible to apply, with the same leakage current, a higher counter-voltage to the rectifier.
  • the drawing shows a preferred embodiment of the apparatus for practicing the method described hereinafter.
  • These means may consist, for example, in having the rectifier plate placed during the passage of current on a supporting plate of high thermal capacity, which plate is heated to the temperature which is also the desired temperature during the forming process of the rectifier. If due to the passage of current an excessive amount of heat is locally developed in the rectifier, the heating plate acts at the same time as a means of carrying oil. the excessive heat and therefore of obtaining a uniform temperature over the whole of the surface of the rectifier. Also other means are possible for achieving this purpose. For example, a current of .air may be directed upon the rectifier plate.
  • Another embodiment consists in the rectifier being placed in a bath containing an insulating liquid whose boiling point corresponds to the temperature which is desired for the formation of the rectifier.
  • This method has the advantage that the temperature of the rectifier during the formation can be fixed with extremely high accuracy.
  • the forming device may beutilized for other rectifier plates so that these devices are utilized as efficiently as possible.
  • This is still further promoted by submitting the rectifier to a first treatment by heat and current wherein an increase of temperature is produced exclusively by the heat due to the current, said treatment being followed by a treatment by heat and current wherein heat is supplied to the rectifier from the outside, for example, by a heating plate which supports the rectifier.
  • the heating plates are only in use during part-of the forming period of the rectifier.
  • Use may be made of direct voltage, of pulsating direct voltage or of alternating voltage in cir'-, wit-arrangements suited therefor.
  • a layer of selenium into which admixtures are introduced in order to increase the conductivity is applied to a disc of iron or aluminum on which is provided an intermediate layer inter alia of carbon to ensure a satisfactory adherence while maintaining 'a good electrical contact.
  • the whole of it is submitted to a thermal treatment in order to convert the selenium into the con- 60 ducting modification and to form the blocking layer on the surface of the selenium layer.
  • a substance producing an alkaline reaction such as piperidene may be applied during the thermal treatment in finely divided condition to the selenium surface.
  • the above-mentioned alloy is sprayed on to the blocking layer.
  • rectifiers thus manufactured which have a surface area of 100 sq. cms. allow the passage in the forward direction of a current of 30 amperes when a pulsating voltage having a peak value of 2.2 volts is applied.
  • the countervoltage i. e. the voltage which has to be applied to cause a ourrent of 100 ma. to flow in the opposite direction, amounts to about 10 volts.
  • the rectifiers manufactured according to the above example are submitted for about 1 minute to a treatment by current (forming proccess) during which such a current is led in the opposite direction through the rectifiers that there occurs an increase in temperature to about 125 0., that is above the melting temperature of the alloy, it is found that after cooling the forward current amounts to 2'1 amps. but that the countervoltage has increased to 20 volts with a current of 0.1 amp.
  • the formin process is repeated for about four minutes up to a temperature near C.
  • Rectifiers having an operative surface area of 12 sq. cms. are measured after the manufacture and prior to the formation.
  • the forward current measured at an applied direct-current voltage of 2 volts, amounts to 4 amps.
  • the leakage current is 100 ma. at a pulsating voltage of '9 volts.
  • the rectifiers are formed in order to increase the co'untervoltage, during which process the countercurrent passing through the rectifiers gives rise to an increase in the temperature thereof up'to C. This operation is only of short duration and lasts from 20 to 30 seconds.
  • the forward current is likewise 4 amps. but that the countervoltag'e at 100 ma. has increased to 16 volts.
  • the rectifiers remain in rest for some time, whereafter the forward current and the countercurrent are measured once more. Now the former appears to be 2.7 amps. at 2 volts and the latter 100 ma. at 17 volts.
  • the rectifiers are submitted to a second forming treatment, which lasts about 3 hours and during which the temperature is maintained on the average at 80 0., it is found after termination that the forward current is 2.5 amps. at 2 volts and that the countercurrent has been improved so as to be only'12.5 ma. at a voltage of 18 volts.
  • the indicated values of the voltage are always the peak values of the pulsating voltage or alternating voltage.
  • a rectifier plate I is introduced into a countersunk portion of a block 2 of high thermal capacity which is maintained from the outside, for example by an electric heating element 3, at a constant temperature of about 9Q.
  • a contact member 4 consisting of two parallel metal plates between which are located a plurality of resilient contacts 5 is suspended from a supporting plate 6. The latter is moved by means of a lever I which is supported by a column 8.
  • the resilient contacts 5 are arranged between the plates 4 in such manner that over the whole of the surface of the rectifier plate a uniform distribution of current is obtained. It should be borne in mind that for the formation use is made of a fairly heavy current, viz. of about 3 amps. and over on a rectifying surface area of 140 sq. cms. It is consequently important to distribute the current over a large number of contacts.
  • the contacts 5 are resiliently mounted so that in the case of unevennesses on the rectifier plate notwith tanding a satisfactory contact throughout the whole surface is obtained whilst there occurs the additional advantage that the contact pressure is kept within determined limits so that the risk of the contacts being pressed through the alloy layer and of the blocking layer being damaged is avoided.
  • contact member-4 with the contacts 5 on the one hand and the block 2 on the other hand must be arranged so as to be insulated from one another.
  • the forming current is furnished by a storage battery 12 whose output voltage is regulable, current and voltage being read of! on meters I0 and H.
  • a chronometer completes the equipment of this installation wherein in the present instance one rectifier plate can be treated.
  • an installation is composed of a plurality of the above-described devices so that a plurality of rectifiers can be formed simultaneously.
  • a process for conditioning a selenium rectifier including a counter-electrode comprising the steps of heating said rectifier in an insulating liquid bath to raise the temperature thereof to a first temperature above the melting point of said electrode, -said bath having a boiling point corresponding to said temperature, submitting said rectifier to a forming current in a reverse current flow direction during said heating for a predetermined period, thereafter rest-curing said rectifier for a selected time, reheating said rectifier to a temperature substantially lower than said first temperature, and maintaining a forming current in a reverse current flow direction during the latter heating also.
  • a method of reducing the leakage current of a selenium rectifier comprising the steps of heating said rectifier to a higher temperature than its normal operating temperature by immersing said rectifier in a bath containing an insulating liquid whose boiling point corresponds to said heating temperature, and passing an electric forming current through said rectifier in its perature above the normal operating temperature of said rectifier, and passing an electric forming current through said rectifier in its blockin direction during the maintenance of said higher temperature.
  • a process of manufacturing a selenium rectifier comprising the steps of immersing said rectifier in a bath containing an insulating liquid, heating said bath to a temperature above the normal operating temperature of said rectifier, and passing an electric forming current through said rectifier in its blocking direction of a magnitude which increases the temperature of said rectifier during the maintenance of said higher temperature of said bath.
  • a process of manufacturing a selenium rectifier having a counter-electrode with a given melting point comprising the steps of immersing said rectifier in a bath containing an insulating liquid, heating said bath to a temperature above the melting'point of said counter-electrode for a predetermined period of time, passing an electric forming current through said rectifier during the maintenance of said higher temperature, and thereafter heating the bath having the rectifier immersed therein to a temperature below the melting point of said counter-electrode while passing an electric forming current through said rectifier.
  • a process of manufacturing a selenium rectifier having a counter-electrodewith a given melting point comprising the steps of passing a heating current through said rectifier to heat said rectifier to a temperature above the said melting point of said counter-electrode for a predetermined period of time, ageing said rectifier, reheating said rectifier at a lower temperature by immersing said rectifier in a bath containing an insulating liquid maintained at said lower temperature, and passing an electric forming current through said rectifier in its blocking direction during the maintenance. of said lower temperature.

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US613326A 1941-05-07 1945-08-29 Method of reducing the leakage current in selenium rectifiers Expired - Lifetime US2464066A (en)

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NL606763X 1941-05-07

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US (1) US2464066A (enrdf_load_stackoverflow)
BE (1) BE445491A (enrdf_load_stackoverflow)
FR (1) FR881786A (enrdf_load_stackoverflow)
GB (1) GB606763A (enrdf_load_stackoverflow)
NL (1) NL215047A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2725317A (en) * 1952-04-24 1955-11-29 Bell Telephone Labor Inc Method of fabricating and heat treating semiconductors
US2752542A (en) * 1950-09-23 1956-06-26 Siemens Ag Dry-plate rectifier
US2817607A (en) * 1953-08-24 1957-12-24 Rca Corp Method of making semi-conductor bodies
US2874448A (en) * 1953-02-13 1959-02-24 William F Haldeman Method for stabilizing semi-conductor rectifiers
US2915687A (en) * 1953-12-01 1959-12-01 Itt Electroforming of semiconductive cells

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1935383A (en) * 1931-01-22 1933-11-14 Rca Corp Rectifier element
US2237802A (en) * 1938-06-14 1941-04-08 Gen Electric Method of treating dry plate elements
US2241908A (en) * 1938-06-07 1941-05-13 Suddeutsche App Fabrik G M B H Rectifier device
US2261725A (en) * 1938-05-18 1941-11-04 Westinghouse Electric & Mfg Co Selenium rectifier
US2266922A (en) * 1938-12-28 1941-12-23 Union Switch & Signal Co Manufacture of alternating current rectifiers
US2279187A (en) * 1939-01-11 1942-04-07 Union Switch & Signal Co Alternating electric current rectifier of the selenium type
US2362228A (en) * 1941-06-12 1944-11-07 Bell Telephone Labor Inc Method of forming contacts on metal oxide-metal rectifiers

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1935383A (en) * 1931-01-22 1933-11-14 Rca Corp Rectifier element
US2261725A (en) * 1938-05-18 1941-11-04 Westinghouse Electric & Mfg Co Selenium rectifier
US2241908A (en) * 1938-06-07 1941-05-13 Suddeutsche App Fabrik G M B H Rectifier device
US2237802A (en) * 1938-06-14 1941-04-08 Gen Electric Method of treating dry plate elements
US2266922A (en) * 1938-12-28 1941-12-23 Union Switch & Signal Co Manufacture of alternating current rectifiers
US2279187A (en) * 1939-01-11 1942-04-07 Union Switch & Signal Co Alternating electric current rectifier of the selenium type
US2362228A (en) * 1941-06-12 1944-11-07 Bell Telephone Labor Inc Method of forming contacts on metal oxide-metal rectifiers

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752542A (en) * 1950-09-23 1956-06-26 Siemens Ag Dry-plate rectifier
US2725317A (en) * 1952-04-24 1955-11-29 Bell Telephone Labor Inc Method of fabricating and heat treating semiconductors
US2874448A (en) * 1953-02-13 1959-02-24 William F Haldeman Method for stabilizing semi-conductor rectifiers
US2817607A (en) * 1953-08-24 1957-12-24 Rca Corp Method of making semi-conductor bodies
US2915687A (en) * 1953-12-01 1959-12-01 Itt Electroforming of semiconductive cells

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FR881786A (fr) 1943-05-07
NL215047A (enrdf_load_stackoverflow)
BE445491A (enrdf_load_stackoverflow)
GB606763A (en) 1948-08-19

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