Classifications

• • 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
  • H01L21/12—Application of an electrode to the exposed surface of the selenium or tellurium after the selenium or tellurium has been applied to the foundation plate
• • 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
• • 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
  • H01L21/105—Treatment of the surface of the selenium or tellurium layer after having been made conductive

Definitions

• This invention relates to new and useful improvements in the manufacture of selenium rectifiers, and particularly to the composition and application of counter electrodes.
• selenium rectifiers are built up of layers; a metal base plate, followed by one or more layers including a layer of selenium and a counter electrode.
• the counter electrode may be an alloy of various metals, e. g. cadmium, tin, lead, and bismuth, and it may be sprayed or evaporated on the selenium layer, a thin intermediate layer being preferably interposed between the two.
• the intermediate layer may effect an increase of 25 in the current flow and is customarily selected from the metals belonging to the secondary group of the fourth and fifth groups of the periodic system of elements, e. g. bismuth.
• the intermediate layer retards and may even make impossiblethe customary electric forming process.
• some metal such as thallium, gallium, indium or silver is added to the intermediate layer to aid in the formation of the blocking layer. If 50% of the intermediate layer consists of such additive then forming will proceed satisfactorily, the transfer resistance will be decreased and the current flow increased.
• the alloy or mixture of intermediate layer metal and additive metal may be applied to the selenium by evaporation in a vacuum, insuring the formation of a uniform, thin deposit.
• a mixture or alloy of bismuth and thallium has proved to be very efiective. Since these metals have almost the same melting point they may be deposited in the desired ratio without fractionation.
• the intermediate layer is so chosen that 500 micrograms per square centimeter of metal, but preferably less than 100 micrograms per square centimeter is deposited on the selenium surface.
• a separate evaporator is used for each metal.
• the two evaporators can be close together so that the two steam jets will mix near the evaporators.
• the evaporators or the selenium plates may be moved repeat edly at short intervals and thus vaporize the selenium with both metals.
• the ratio of the two components may be varied by varying the distance of the selenium surface from the two evaporators, by varying the vaporization period, by varying the speed of vaporization or the movement of the selenium surface, etc.
• an additional layer may be applied, e. g. by spraying on it a spray-metal, i. e. an alloy having a low melting point.
• a spray-metal i. e. an alloy having a low melting point.
• bismuth, lead, tin or cadmium, or an alloy of some or all said metals may also be used for this purpose.
• an alloy of tin and cadmium, having a melting point of about 178 C., or Woods metal can also be used to form the counter electrode by spraying it on top of the intermediate layer of bismuth and thallium.
• Such rectifiers could readily be formed and the current flow through them would be 25% higher than through rectifiers equipped with the customary counter electrode.
• a selenium rectifier having a counter electrode, a thin layer intermediate the selenium and the counter electrode consisting of a metal of the secondary group of the fourth and fifth groups of the periodic system of elements, and an additive selected from the group consisting of thallium, indium, and gallium.
• a selenium rectifier having a counter electrode, and a thin layer intermediate the selenium and the counter electrode consisting of bismuth and thallium.

Landscapes

• 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)
• Power Engineering (AREA)
• Electrolytic Production Of Metals (AREA)
• Cell Electrode Carriers And Collectors (AREA)
• Physical Vapour Deposition (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=7478734

Family Applications (1)

Country Status (6)

Cited By (2)

Citations (8)

Family Cites Families (8)

• 0
  • BE BE516364D patent/BE516364A/xx unknown
  • NL NLAANVRAGE7212358,A patent/NL174375B/xx unknown
• 1951
  • 1951-12-20 DE DES26432A patent/DE975845C/de not_active Expired
• 1952
  • 1952-11-13 CH CH314470D patent/CH314470A/de unknown
  • 1952-12-10 US US325212A patent/US2787745A/en not_active Expired - Lifetime
  • 1952-12-12 GB GB31559/52A patent/GB718354A/en not_active Expired

Patent Citations (8)

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