US2446467A - Dry plate rectifier - Google Patents

Dry plate rectifier Download PDF

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US2446467A
US2446467A US563108A US56310844A US2446467A US 2446467 A US2446467 A US 2446467A US 563108 A US563108 A US 563108A US 56310844 A US56310844 A US 56310844A US 2446467 A US2446467 A US 2446467A
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selenium
plates
layer
electrode
methylene iodide
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Stanley S Fry
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Fansteel Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/06—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
    • H01L21/10—Preliminary treatment of the selenium or tellurium, its application to the foundation plate, or the subsequent treatment of the combination
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02425—Conductive materials, e.g. metallic silicides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02436—Intermediate layers between substrates and deposited layers
    • H01L21/02439—Materials
    • H01L21/02491—Conductive materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02656—Special treatments
    • H01L21/02664—Aftertreatments
    • H01L21/02667—Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth

Definitions

  • This invention relates to blocking layer devices such as selenium rectifiers and light sensitive devices, and more specifically to means for improving the characteristics of selenium employed in v the manufacture of the blocking layer devices.
  • a rigid carrier electrode or supporting electrode is provided with a thin coating or layer of selenium.
  • the supporting electrode may be. formed of nickel, nickel-plated iron, aluminum, magnesium, berylium or other metals and alloys.
  • a common practice in the production of selenium rectifiers includes grit blasting the iron disc or plate and plating the disc with nickel. The purpose of the grit blasting is to present a roughened surface to the selenium and to thereby improve the adherence of the selenium to the carrier electrode. The disc is then thoroughly cleaned and a thin film of selenium is applied over the nickel layer.
  • the selenium film or layer may be formed by a variety. of methods.
  • the plate or disc may be heated t6 a temperature above the melting point of selenium, for example, to a temperature of from 230 to 250 0., and the selenium in stick form ma be rubbed across the heated plate in orderto melt the selenium and form the desired film.
  • Another method of application includes placing a, measured quantity of powdered selenium or selenium in pellet form on the heated plate and flowing the melted selenium over the surface.
  • the melted selenium is usually spread over the heated plate by mechanical means, as with a glass rod.
  • the selenium may also be deposited on the carrier electrode from a vapor phase. The vaporization method is commonly employed in depositing the selenium film upon the light metal carrier electrodes.
  • the selenium is then transformed into its gray, crystalline state by heat treatment.
  • the coated discs are generally stacked with mica, aluminum or other inert, smooth-surfaced discs or washers in contact with the selenium and between adjacent plates, and the stack subjected to a moderate pressure.
  • the stacks under pressure are then subjected to a relatively low temperature, that is, a temperature below 150 C., and maintained at this temperature for from one hour to four or five hours.
  • a relatively low temperature that is, a temperature below 150 C., and maintained at this temperature for from one hour to four or five hours.
  • the selenium softens so that the pressure produces a layer of selenium of relatively uniform thickness and having a smooth surface.
  • the stacks are withdrawn from the oven or heat treating furnace and the plates are removed 2 from the stack.
  • the plates are then given a further heat treatment at a temperature approaching the melting point of selenium.
  • This heat treatment is generally conducted at temperatures between about 200 C. and the melting point of selenium, for example, about 210 C., for a period of from fifteen minutes to several hours.
  • a layer of more or less uniform thickness of selenium is produced having a. smooth surface and the selenium is transformed from its amorphous, non-conducting form into its gray, crystalline, conducting form.
  • the smooth surface of the selenium film is then treated to form a blocking layer and a counterelectrode consisting of a relatively low melting point alloy is applied, as by spraying, over the selenium coating.
  • the final step in the manufacture of the rectifier plates consists of an electrical forming treatment.
  • This treatment consists of subjecting the plate to either an alternating or direct current until a high resistance is developed in the reverse direction.
  • This step may consist of applying to the plate in the reverse direction a direct current voltage of below about 15 volts or a ward direction of the rectifier plate.
  • the voltage may be about 20 volts and the period required for forming is generally greater than that required when a direct current is employed because only one-half cycle of the current flows in the reverse direction.
  • Light sensitive devices of the blocking layer class are produced in a similar manner.
  • a supporting electrode is provided with a thin film or layer of selenium in its gray, crystalline modification and an artificial blocking layer formed on the surface of the selenium.
  • a second electrode is then applied over the treated surface of the selenium.
  • This electrode may consist of a light permeable film of metal or a metal grid. The application of the light-permeable metal may be accomplished by any of the methods known to the art.
  • the present invention is directed to means for improving the conductivity of the selenium layer in the forward direction.
  • the invention is not limited to any specific form, type or composition known methods.
  • any desired method may be employed in forming an artificial blocking layer on the selenium surface.
  • any means for electrically forming the rectifier plates may be employed.
  • the principal object of this invention is to improve the forward conductivity of the selenium layer in blocking layer devices.
  • a further object of this invention is to increase the ratio of the resistance in the reverse direction as compared to the resistance in the forward direction.
  • the present invention contemplates incorporating in the selenium film or layer a small amount of methylene iodide
  • the specific details of the manufacturing process are dependent upon the type of unit being made and the class of service for which it is desired. For purposes of illustration the production of selenium rectifier plates is described.
  • the methylene iodide is added to molten selenium in the proportions of from about 0.05 cc. to about 0.5 00., preferably about 0.1 cc., to 100 grams of selenium.
  • the selenium is melted and agitated vigorously while the methylene iodide is added. The mass is then cast promptly into the desired form.
  • the carrier electrode for example, a nickelplated iron disc is provided with a layer or film of the doped selenium in its gray, crystalline form.
  • This layer may be formed by heating the carrier electrode and applying the doped selenium in powdered form or by rubbing a stick of doped selenium over the heated carrier electrode.
  • the resulting film or layer is then transformed into its gray, crystalline form by the usual heat treatment.
  • the selenium surface is then treated to form an artificial blocking layer by any of the
  • the counter-electrode is then applied by spraying a low melting point alloy over the treated selenium surface.
  • the rectifier plate is completed by subjecting the composite unit to an electrical forming process.
  • the plates were subsequently provided with a counterelectrode and then subjected to the same electrical forming operation.
  • the plates formed from untreated selenium were intended as standard or control plates.
  • a rectified direct current voltage of 1 volt was applied to the individual plates of each series in the reverse and in the forward directions and the current flow measured.
  • the leakage current or reverse current flow in the standard or control plates averaged approximately 0.35 milliampere and the forward current flow in these plates averaged approximately 0.42 ampere.
  • the rectification ratio of these plates was 1: 1200.
  • the leakage current or reverse current flow in the case of the plates made in accordance with the present invention averaged approximately 0.40 milliampere.
  • the forward current flow in these plates averaged approximately 0.83 ampere.
  • the rectification factor of such plates was 1:2075.
  • the current flow through the individual plates of both series was also measured at an applied rectified direct current voltage of 3 volts.
  • the leakage current flow in the case of the standard or control plates averaged approximately 1.2 milliamperes and the forward current flow averaged approximately 2.5 amperes.
  • the rectification ratio at 3 volts for these plates was 1:2083,
  • the leakage current or reverse current flow in the case of the plates made from the doped selenium averaged approximately 1.35 milliamperes and the forward current flow averaged approximately 4.4 amperes.
  • the rectification ratio for this series of plates at 3 volts was 1 3260.
  • the method of producing blocking layer de-- vices which comprises adding a small amount of methylene iodide to selenium, providing a supporting electrode wtih a layer of gray, crystalline selenium containing the methylene iodide, forming a blocking layer on the surface of the selenium layer and applying a counter-electrode over the treated selenium surface.
  • blocking layer de-- vices which comprises adding a small amount of methylene iodide to selenium, applying a layer of the selenium containing the methylene iodide to a supporting electrode, transforming the selenium into its gray, crystalline form, forming a blocking layer on the selenium surface and applying a counter-electrodeover the treated selenium surface.
  • the method of producing blocking layer devices which comprises adding methylene iodide to selenium in the relative proportions of from about 0.05 cc. to about 0.5 cc. methylene iodide per gms. of selenium, applying a layer of the selenium containing the methylene iodide to a supporting electrode, transforming the selenium into its gray, crystalline form, forming a blocking layer on the selenium surface and applying a counterelectrode over the treated selenium surface.
  • a 4 The method of producing selenium rectifier plates which comprises adding a small amount of methylene iodide to selenium, providing a sup porting electrode with a layer of gray, crystalline selenium containing the methylene iodide, forming a blocking layer on the surface of the selenium layer, applying a counter-electrode over the treated selenium sunface and subjecting the composite unit toan electrical forming operation.
  • the method of producing selenium rectifier plates which comprises adding to selenium a small amount of methylene iodide, app ying a layer of the selenium containing the methylene iodide to a supporting electrode, transforming the selenium into its gray, crystalline form, forming a blocking layer on the selenium surface, applying a counter-electrode over the treated selenium surface and subjecting the composite unit to an electrical forming operation.
  • the method of improving the conductivity of selenium which comprises incorporating in selenium from about 0.05 cc. to about 0.5 cc. methylene iodide per 100 gms. selenium.
  • a blocking layer device comprising a carrier electrode, a layer of selenium to which has been added a small amount of metirvleneiodide and a counter-electrode.
  • a blocking layer device comprising a carrier electrode, a counter-electrode and an intermediate'layer of selenium .to which has been added from about 0.05 cc. to about 0.5 cc. methylene iodide per l00 gms. of selenium.
  • a selenium rectifier comprising a carrier electrode, a counter-electrode and an intermediate layer of gray, crystalline selenium to which has been added a small amount of methylene Y iodide.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
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  • Chemical & Material Sciences (AREA)
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  • Crystallography & Structural Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Description

Patented Aug. 3, 1948 par PLATE RECTIFIER Stanley S. Fry, North Chicago, Ill., assignor to Fansteel Metallurgical Corporation, North Chicago, 11]., a corporation of New York No Drawing. Application November 11, 1944, Serial No. 563.108
11 Claims. I l
This invention relates to blocking layer devices such as selenium rectifiers and light sensitive devices, and more specifically to means for improving the characteristics of selenium employed in v the manufacture of the blocking layer devices.
In the production of blocking layer devices having a semi-conductor layer, for example, selenium rectifiers, a rigid carrier electrode or supporting electrode is provided with a thin coating or layer of selenium. The supporting electrode may be. formed of nickel, nickel-plated iron, aluminum, magnesium, berylium or other metals and alloys. A common practice in the production of selenium rectifiers includes grit blasting the iron disc or plate and plating the disc with nickel. The purpose of the grit blasting is to present a roughened surface to the selenium and to thereby improve the adherence of the selenium to the carrier electrode. The disc is then thoroughly cleaned and a thin film of selenium is applied over the nickel layer.
The selenium film or layer may be formed by a variety. of methods. The plate or disc may be heated t6 a temperature above the melting point of selenium, for example, to a temperature of from 230 to 250 0., and the selenium in stick form ma be rubbed across the heated plate in orderto melt the selenium and form the desired film. Another method of application includes placing a, measured quantity of powdered selenium or selenium in pellet form on the heated plate and flowing the melted selenium over the surface. The melted selenium is usually spread over the heated plate by mechanical means, as with a glass rod. The selenium may also be deposited on the carrier electrode from a vapor phase. The vaporization method is commonly employed in depositing the selenium film upon the light metal carrier electrodes.
The selenium is then transformed into its gray, crystalline state by heat treatment. The coated discs are generally stacked with mica, aluminum or other inert, smooth-surfaced discs or washers in contact with the selenium and between adjacent plates, and the stack subjected to a moderate pressure. The stacks under pressure are then subjected to a relatively low temperature, that is, a temperature below 150 C., and maintained at this temperature for from one hour to four or five hours. During this stage of the heat treatment the selenium softens so that the pressure produces a layer of selenium of relatively uniform thickness and having a smooth surface. I
The stacks are withdrawn from the oven or heat treating furnace and the plates are removed 2 from the stack. The plates are then given a further heat treatment at a temperature approaching the melting point of selenium. This heat treatment is generally conducted at temperatures between about 200 C. and the melting point of selenium, for example, about 210 C., for a period of from fifteen minutes to several hours. During the combined heat treatment, a layer of more or less uniform thickness of selenium is produced having a. smooth surface and the selenium is transformed from its amorphous, non-conducting form into its gray, crystalline, conducting form.
The smooth surface of the selenium film is then treated to form a blocking layer and a counterelectrode consisting of a relatively low melting point alloy is applied, as by spraying, over the selenium coating.
The final step in the manufacture of the rectifier plates consists of an electrical forming treatment. This treatment consists of subjecting the plate to either an alternating or direct current until a high resistance is developed in the reverse direction. This step may consist of applying to the plate in the reverse direction a direct current voltage of below about 15 volts or a ward direction of the rectifier plate. The voltage may be about 20 volts and the period required for forming is generally greater than that required when a direct current is employed because only one-half cycle of the current flows in the reverse direction. I
Light sensitive devices of the blocking layer class are produced in a similar manner. A supporting electrode is provided with a thin film or layer of selenium in its gray, crystalline modification and an artificial blocking layer formed on the surface of the selenium. A second electrode is then applied over the treated surface of the selenium. This electrode may consist of a light permeable film of metal or a metal grid. The application of the light-permeable metal may be accomplished by any of the methods known to the art.
The present invention is directed to means for improving the conductivity of the selenium layer in the forward direction. The invention is not limited to any specific form, type or composition known methods.
of carrier electrode or counterelectrode. Any desired method may be employed in forming an artificial blocking layer on the selenium surface. In the preparation of selenium rectifier plates any means for electrically forming the rectifier plates may be employed.
The principal object of this invention is to improve the forward conductivity of the selenium layer in blocking layer devices.
A further object of this invention is to increase the ratio of the resistance in the reverse direction as compared to the resistance in the forward direction.
Other objects and advantages of this invention will become apparent from the following description and claims.
The present invention contemplates incorporating in the selenium film or layer a small amount of methylene iodide The specific details of the manufacturing process are dependent upon the type of unit being made and the class of service for which it is desired. For purposes of illustration the production of selenium rectifier plates is described.
The methylene iodide is added to molten selenium in the proportions of from about 0.05 cc. to about 0.5 00., preferably about 0.1 cc., to 100 grams of selenium. The selenium is melted and agitated vigorously while the methylene iodide is added. The mass is then cast promptly into the desired form.
The carrier electrode. for example, a nickelplated iron disc is provided with a layer or film of the doped selenium in its gray, crystalline form. This layer may be formed by heating the carrier electrode and applying the doped selenium in powdered form or by rubbing a stick of doped selenium over the heated carrier electrode. The resulting film or layer is then transformed into its gray, crystalline form by the usual heat treatment. The selenium surface is then treated to form an artificial blocking layer by any of the The counter-electrode is then applied by spraying a low melting point alloy over the treated selenium surface. The rectifier plate is completed by subjecting the composite unit to an electrical forming process.
The addition of these small amounts of methylene iodide to the selenium decreases appreciably the forward resistance of the selenium and decreases the ratio between the current flow in the reverse direction and the current flow in the forward direction upon the application of a direct current voltage to the plate in the reverse and forward directions. An ideal or theoretically perfect rectifier plate would have no current flow in the reverse direction and the rectification ratio would be zero.
In order to compare the rectification ratio of rectifier plates formed with selenium and rectifier plates formed with selenium containing small amounts of methylene iodide, a sample of sele-' nium was divided into two portions. One portion was heated to about 350 C. and 0.1 cc. methylene iodide added per 100 grams of selenium. The mass was agitated vigorously durin the addition and was then cast in stick form. The other porsticks over the heated plates and spreading the melted material over the surface with a glass rod. The plates were then stacked with mica discs covering the selenium layer and the stacks placed under pressure. The stacks were heated to about 140 C. and maintained at this temperature for about 2 hours after which the pressure was retion of selenium was melted and cast in stick moved and the plates heated to about 210 C. and maintained at this temperature for about 5 2 hour.
The plates were subsequently provided with a counterelectrode and then subjected to the same electrical forming operation. The plates formed from untreated selenium were intended as standard or control plates.
A rectified direct current voltage of 1 voltwas applied to the individual plates of each series in the reverse and in the forward directions and the current flow measured. The leakage current or reverse current flow in the standard or control plates averaged approximately 0.35 milliampere and the forward current flow in these plates averaged approximately 0.42 ampere. The rectification ratio of these plates was 1: 1200.
The leakage current or reverse current flow in the case of the plates made in accordance with the present invention averaged approximately 0.40 milliampere. The forward current flow in these plates averaged approximately 0.83 ampere. The rectification factor of such plates was 1:2075.
The current flow through the individual plates of both series was also measured at an applied rectified direct current voltage of 3 volts. The leakage current flow in the case of the standard or control plates averaged approximately 1.2 milliamperes and the forward current flow averaged approximately 2.5 amperes. The rectification ratio at 3 volts for these plates was 1:2083,
The leakage current or reverse current flow in the case of the plates made from the doped selenium averaged approximately 1.35 milliamperes and the forward current flow averaged approximately 4.4 amperes. The rectification ratio for this series of plates at 3 volts was 1 3260.
The foregoing numerical values of current ilow 'will differ with different plate areas and also with diiferent grades and samplesof selenium. These values, however, are representative of the characteristics imparted by the addition of methylene iodide to selenium and the improvements realized by the use of the doped selenium are apparent from this data.
I claim:
1. The method of producing blocking layer de-- vices which comprises adding a small amount of methylene iodide to selenium, providing a supporting electrode wtih a layer of gray, crystalline selenium containing the methylene iodide, forming a blocking layer on the surface of the selenium layer and applying a counter-electrode over the treated selenium surface.
. 2. The method of producing blocking layer de-- vices which comprises adding a small amount of methylene iodide to selenium, applying a layer of the selenium containing the methylene iodide to a supporting electrode, transforming the selenium into its gray, crystalline form, forming a blocking layer on the selenium surface and applying a counter-electrodeover the treated selenium surface.
3. The method of producing blocking layer devices which comprises adding methylene iodide to selenium in the relative proportions of from about 0.05 cc. to about 0.5 cc. methylene iodide per gms. of selenium, applying a layer of the selenium containing the methylene iodide to a supporting electrode, transforming the selenium into its gray, crystalline form, forming a blocking layer on the selenium surface and applying a counterelectrode over the treated selenium surface.
a 4. The method of producing selenium rectifier plates which comprises adding a small amount of methylene iodide to selenium, providing a sup porting electrode with a layer of gray, crystalline selenium containing the methylene iodide, forming a blocking layer on the surface of the selenium layer, applying a counter-electrode over the treated selenium sunface and subjecting the composite unit toan electrical forming operation.
5. The method of producing selenium rectifier plates which comprises adding to selenium a small amount of methylene iodide, app ying a layer of the selenium containing the methylene iodide to a supporting electrode, transforming the selenium into its gray, crystalline form, forming a blocking layer on the selenium surface, applying a counter-electrode over the treated selenium surface and subjecting the composite unit to an electrical forming operation.
6. The method of improving the conductivity of selenium which comprises incorporating in selenium a small amount of methylene iodide.-
7. The method of improving the conductivity of selenium which comprises incorporating in selenium from about 0.05 cc. to about 0.5 cc. methylene iodide per 100 gms. selenium.
8. The method of improving the conductivity of selenium which comprises melting selenium and incorporating in the molten selenium a small amount of methylene iodide.
9. A blocking layer device comprising a carrier electrode, a layer of selenium to which has been added a small amount of metirvleneiodide and a counter-electrode.
10. A blocking layer device comprising a carrier electrode, a counter-electrode and an intermediate'layer of selenium .to which has been added from about 0.05 cc. to about 0.5 cc. methylene iodide per l00 gms. of selenium.
11. A selenium rectifier comprising a carrier electrode, a counter-electrode and an intermediate layer of gray, crystalline selenium to which has been added a small amount of methylene Y iodide.
STANLEY B. FRY.
REFERENCES CITED The following references are of record in the file of this patent:
. UNITED STATES PATENTS Handbook of Chemistry and Physics, 26th edition, 1942-1943; Chemical Rubber Publishing 00., pages 880-881.
US563108A 1944-11-11 1944-11-11 Dry plate rectifier Expired - Lifetime US2446467A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2637770A (en) * 1945-07-13 1953-05-05 Purdue Research Foundation Alloys and rectifiers made thereof
US2653374A (en) * 1949-04-01 1953-09-29 Int Standard Electric Corp Electric semiconductor
US2747254A (en) * 1952-06-14 1956-05-29 Westinghouse Electric Corp Manufacture of selenium rectifiers
US2755536A (en) * 1951-11-07 1956-07-24 Ibm Method of producing transistors having substantially uniform characteristics
US2784478A (en) * 1952-08-20 1957-03-12 Rca Corp Electroforming semi-conductor devices

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2162613A (en) * 1936-08-13 1939-06-13 Philips Nv Electrode system and method of making same
US2173249A (en) * 1935-10-30 1939-09-19 Philips Nv Asymmetric electrode system
US2175016A (en) * 1936-06-20 1939-10-03 Gen Electric Method of producing selenium rectifiers or the like
US2189576A (en) * 1935-06-22 1940-02-06 Gen Electric Dry plate rectifier and method of producing same
US2226715A (en) * 1939-03-08 1940-12-31 Suddeutsche App Fabrik G M B H Rectifier device
US2227827A (en) * 1938-09-21 1941-01-07 Union Switch & Signal Co Manufacture of devices presenting electrical asymmetric conductivity
US2316905A (en) * 1939-07-01 1943-04-20 Westinghouse Electric & Mfg Co Selenium rectifier

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2189576A (en) * 1935-06-22 1940-02-06 Gen Electric Dry plate rectifier and method of producing same
US2173249A (en) * 1935-10-30 1939-09-19 Philips Nv Asymmetric electrode system
US2175016A (en) * 1936-06-20 1939-10-03 Gen Electric Method of producing selenium rectifiers or the like
US2162613A (en) * 1936-08-13 1939-06-13 Philips Nv Electrode system and method of making same
US2227827A (en) * 1938-09-21 1941-01-07 Union Switch & Signal Co Manufacture of devices presenting electrical asymmetric conductivity
US2226715A (en) * 1939-03-08 1940-12-31 Suddeutsche App Fabrik G M B H Rectifier device
US2316905A (en) * 1939-07-01 1943-04-20 Westinghouse Electric & Mfg Co Selenium rectifier

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2637770A (en) * 1945-07-13 1953-05-05 Purdue Research Foundation Alloys and rectifiers made thereof
US2653374A (en) * 1949-04-01 1953-09-29 Int Standard Electric Corp Electric semiconductor
US2755536A (en) * 1951-11-07 1956-07-24 Ibm Method of producing transistors having substantially uniform characteristics
US2747254A (en) * 1952-06-14 1956-05-29 Westinghouse Electric Corp Manufacture of selenium rectifiers
US2784478A (en) * 1952-08-20 1957-03-12 Rca Corp Electroforming semi-conductor devices

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