US2129410A - Manufacture of electrical rectifiers - Google Patents

Manufacture of electrical rectifiers Download PDF

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Publication number
US2129410A
US2129410A US46358A US4635835A US2129410A US 2129410 A US2129410 A US 2129410A US 46358 A US46358 A US 46358A US 4635835 A US4635835 A US 4635835A US 2129410 A US2129410 A US 2129410A
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US
United States
Prior art keywords
blank
temperature
elements
oxidized
approximately
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US46358A
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English (en)
Inventor
Philip H Dowling
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Rail STS USA Inc
Original Assignee
Union Switch and Signal Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Union Switch and Signal Inc filed Critical Union Switch and Signal Inc
Priority to US46358A priority Critical patent/US2129410A/en
Priority to GB5636/36A priority patent/GB470973A/en
Priority to DEW98626D priority patent/DE755790C/de
Priority to FR808549D priority patent/FR808549A/fr
Application granted granted Critical
Publication of US2129410A publication Critical patent/US2129410A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
    • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
    • H10P14/29—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials characterised by the substrates
    • H10P14/2901—Materials
    • H10P14/2923—Materials being conductive materials, e.g. metallic silicides
    • 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
    • H10D48/07—Manufacture or treatment of devices having bodies comprising cuprous oxide [Cu2O] or cuprous iodide [CuI]
    • H10D48/071—Preparation of the foundation plate, preliminary treatment oxidation of the foundation plate or reduction treatment
    • H10D48/074—Oxidation and subsequent heat treatment of the foundation plate
    • 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
    • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
    • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
    • H10P14/203—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials using transformation of metal, e.g. oxidation or nitridation
    • 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
    • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
    • H10P14/20—Formation of materials, e.g. in the shape of layers or pillars of semiconductor materials
    • H10P14/34—Deposited materials, e.g. layers
    • H10P14/3402—Deposited materials, e.g. layers characterised by the chemical composition
    • H10P14/3434—Deposited materials, e.g. layers characterised by the chemical composition being oxide semiconductor materials

Definitions

  • My invention relates to the manufacture of electrical rectifiers, and particularly to the manufacture of rectifier elements for copper oxide rec-
  • One object of my invention is to improve the rectifying, characteristics of the rectifier elements.
  • Fig. 1 is a view showing in elevation one form of blank ready to be prepared as a rectifier element in accordance with one process of manufacture embodying my invention.
  • Fig. 2 is a view showing a number of blanks assembled on a support as they appear during one step in the process of manufacture.
  • Fig. 3 is a vertical sectional view showing, in an exaggerated form, a rectifier element as it appears in another step in the process of manufacture embodying my invention.
  • Fig. 4 is a view, showing a completed rectifier element, constructed in accordance with my invention.
  • a number of copper blanks which may, for example, be-similar to the blank A shown in Fig. 1, are first cleaned in any suitable manner, as by a sand blast, and these blanks are then assembled in pairs on a suitable support B in the manner shown in Fig. 2 so that the blanks of each pair have their adjacent faces A in contact.
  • the blanks are then heated in the presence of air in an electric furnace, the temperature of which is usually maintained at about 1860 F. This heating of the blanks causes a layer of red or cuprous oxide to be formed on the blanks, and is continued until the cuprous oxide layer is of the desired thickness.
  • each blank is then transferred immediately to a second furnace which is maintained at a temperature of approximately 1050 F., and are allowed to remain in this latter furnace only for a sufficient length of time to permit them to cool down to the temperature of the second furnace.
  • the oxidized blanks are then removed from the second furnace and are suddenly cooled or quenched as by plunging the blanks into cold water or a current of cold air.
  • Each blank then appears as shown in Fig. 3 from which it will be seen that each blank A is now covered with an inner coating D of cuprous or red oxide of copper and a thin outer coating C of black oxide of copper. It will also be seen from an inspection of Fig.
  • Rectifier elements of the type described exhibit the characteristic of offering a relatively low resistance to current flowing through the elements from the cuprous oxide to the copper and a relatively high resistance to the flow of current through the elements in the opposite direction.
  • the resistance of the elements in the low resistance direction will hereinafter be referred to as the conducting resistance, while the resistance of the elements in the high resistance direction will hereinafter be referred to as the blocking resistance.
  • the rectifying characteristics of the rectifier elements can be improved to a marked degree.
  • This modification consists primarily in retaining the oxidized blanks in the second furnace for a longer period of time than is required to just cool these blanks to the quenching temperature.
  • the time required to cool the blanks to the quenching temperature is about four minutes, and the rectifying characteristics of the elements for most practical purposes will continue to be improved as the time during which the oxidized blanks are retained at the quenching temperature increases, at least until this time exceeds two hours.
  • the time during which the blanks are retained at the quenching temperature will, for convenience, be referred to hereinafter as the annealing time.
  • the principal effect of subjecting the oxidized blanks to an annealing time in the manner just described appears to be to reduce the resistance of the elements in the low resistance direction.
  • This reduction in the resistance of the elements in the low resistance direction is accompanied by a decrease in the resistance of the elements in the high resistance direction.
  • the amount of the decrease in either direction is also a function of the voltage which is impressed on the ele-' ments.
  • the decrease in resistance of the elements in both the high resistance and the low resistance directions due to the annealing time appears to be a maximum at about .2 volt for relatively short annealing times.
  • rectifying ratio that is, the ratio of the current which fiows through the element in thelow resistance direction at a specified voltage to that which flows through the element in the high resistance direction at the same or someother specified voltage. and it is desirable that this ratio should be as high as possible.
  • the voltage which is impressed on the elements in both the low resistance and high resistance directions will be the same, but under most operating conditions, the voltage which is impressed ,on the elements in the high resistance direction will be several times higher than the voltage which is impressed on the elements in the low resistance direction.
  • the operating voltage which is generally impressed on the elements in the high resistance direction is about 4 volts
  • the operating voltage which is generally impressed on the elements in the low resistance direction varies between .2 and .5 volt.
  • the rectifying ratio is improved by increasing the annealing time as long as the voltage to which the elements are subjected in the low resistance direction is less than .5 volt and the voltage to which the elements are subjected in the high resistance direction is about 4 volts.
  • this improvement becomes greater as the voltage in the low resistance direction decreases. For any given conducting direction voltage.
  • the rectifying ratio becomes greater the longer the annealing time, it shows a saturating tendency. That is to say, for any given voltage between .2 volt and .5 volt in the low resistance direction and about 4 volts in the high resistance direction, the rectifying ratio does not increase indefinitely with increases in the annealing time.
  • the rectifying ratio first increases and then decreases with increases in the annealing time. It will be seen, therefore, that when the elements are operated at the same voltage in both the low resistance and the high resistance directions, an optimum annealing time exists above which the rectifying ratio will not be improved. For most practical purposes, however the annealing time that can be profitably em-' ployed, at least in so far as the rectifying ratio is concerned, is limited only to the extent that the added gains would not Justify the added expense.
  • the annealing time appears to improve the uniformity of the resistance of the elements in the high resistance direction, and also to improve the aging characteristics of the elements.
  • the oxidation time with a furnace having sufficient thermal capacity to bring the blanks up to the oxidation temperature in a relatively. short time, is usually between eight and thirteen minutes. If this time is decreased to five minutes, the annealing time remaining constant, the resistance of the elements in the high resistance direction will be about the same as if the elements had been oxidized for thirteen minutes.
  • the resistance of the elements in the high resistance direction appears to be lower at low operating voltages and higher at high operating voltages than that of elements which have been oxidized for either thirteen minutes or five minutes.
  • the magnitude of the blocking resistances which are obtained for oxidation times between thirteen minutes and five minutes are somewhat erratic, but good blocking resistance characteristics can be obtained with short oxidation times coupled with relatively long annealing times.
  • This latter heat treatment consists in baking the elements at a relatively low temperature for a relatively long period of time at some time after the oxidized blanks have been quenched.
  • the temperature at which the elements are baked is not critical and may, for example, be in the neighborhood of 212 F.
  • the baking time is likewise not critical and may be in the neighborhood of 16 to 72 hours. It should be noted, however, that as the baking temperature is decreased, the baking time should be increased.
  • the baking operation will usually be performed after the elements have been assembled into a rectifying unit, but it can, if desired, be performed immediately after the quenching operation.
  • One eifect of the low temperature bake is to decrease the tendency of the elements to break down and short-circuit when subjected to high voltage surges in the high resistance direction.
  • Another effect of the low temperature bake is to improve the aging characteristics of the elements. It should be particularly pointed out that baking the elements produces a beneficial effect on the elements whether or not the elements are subjected to an annealing time.
  • One advantage of the manufacturing process embodying my present invention is that elements which are manufactured by this process operate at higher eificiencies and lower temperatures than it has heretofore been possible to obtain, thus making it possible to increase their output at a given temperature or to obtain a given output at a lower temperature, and thereby decrease the aging of the rectifier.
  • the high efficiency of the elements is also useful in connection with meter rectifiers, and the low resistance is useful in such applications as the snubbing of relays, or the absorption of the inductive discharge from a magnet when its circuit is opened.

Landscapes

  • Thermistors And Varistors (AREA)
  • Rectifiers (AREA)
  • Apparatuses And Processes For Manufacturing Resistors (AREA)
US46358A 1935-10-23 1935-10-23 Manufacture of electrical rectifiers Expired - Lifetime US2129410A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US46358A US2129410A (en) 1935-10-23 1935-10-23 Manufacture of electrical rectifiers
GB5636/36A GB470973A (en) 1935-10-23 1936-02-25 Improvements relating to the manufacture of electrical rectifiers of the dry surfacecontact type
DEW98626D DE755790C (de) 1935-10-23 1936-04-23 Verfahren zur Herstellung von Kupferoxyd-Gleichrichterplatten
FR808549D FR808549A (fr) 1935-10-23 1936-06-15 Perfectionnements dans la fabrication des dispositifs électriques à conductibilits' unilatérale

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US46358A US2129410A (en) 1935-10-23 1935-10-23 Manufacture of electrical rectifiers

Publications (1)

Publication Number Publication Date
US2129410A true US2129410A (en) 1938-09-06

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ID=21943030

Family Applications (1)

Application Number Title Priority Date Filing Date
US46358A Expired - Lifetime US2129410A (en) 1935-10-23 1935-10-23 Manufacture of electrical rectifiers

Country Status (4)

Country Link
US (1) US2129410A (fr)
DE (1) DE755790C (fr)
FR (1) FR808549A (fr)
GB (1) GB470973A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2743201A (en) * 1952-04-29 1956-04-24 Hughes Aircraft Co Monatomic semiconductor devices
US3107197A (en) * 1956-04-18 1963-10-15 Int Resistance Co Method of bonding a metal to a plastic and the article produced thereby

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1746511A (en) * 1927-05-26 1930-02-11 Samuel J M Allen Alternating-current rectifying element
NL31162C (fr) * 1927-11-27 1900-01-01
DE581159C (de) * 1931-02-12 1933-07-22 Siemens & Halske Akt Ges Verfahren zur Behandlung von kompakten Kupferoxydulkoerpern

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2743201A (en) * 1952-04-29 1956-04-24 Hughes Aircraft Co Monatomic semiconductor devices
US3107197A (en) * 1956-04-18 1963-10-15 Int Resistance Co Method of bonding a metal to a plastic and the article produced thereby

Also Published As

Publication number Publication date
FR808549A (fr) 1937-02-09
GB470973A (en) 1937-08-25
DE755790C (de) 1953-06-01

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