US2608611A - Selenium rectifier including tellurium and method of making it - Google Patents

Selenium rectifier including tellurium and method of making it Download PDF

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Publication number
US2608611A
US2608611A US110684A US11068449A US2608611A US 2608611 A US2608611 A US 2608611A US 110684 A US110684 A US 110684A US 11068449 A US11068449 A US 11068449A US 2608611 A US2608611 A US 2608611A
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United States
Prior art keywords
selenium
layer
tellurium
resistance
barrier
Prior art date
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Expired - Lifetime
Application number
US110684A
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English (en)
Inventor
John N Shive
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AT&T Corp
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Bell Telephone Laboratories 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
Priority to NL666602926A priority Critical patent/NL154007B/xx
Priority to BE495728D priority patent/BE495728A/xx
Priority to NL80468D priority patent/NL80468C/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US110684A priority patent/US2608611A/en
Priority to DEW1790A priority patent/DE919360C/de
Priority to FR1018535D priority patent/FR1018535A/fr
Priority to GB20227/50A priority patent/GB668059A/en
Application granted granted Critical
Publication of US2608611A publication Critical patent/US2608611A/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
    • 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
    • H10D48/042—Preparation of foundation plates
    • 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
    • H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
    • 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 selenium rectifiers and to methods of making them.
  • Devices of the typeto which this invention pertains comprise, in general, a metallic backin member or electrode, for example of nickel or aluminum, a layer of selenium upon one face ofithebacking member, and a front electrode, for example of a metal. such as tin, or an alloy, such as oftin, bismuthand cadmium, upon the outer face of the selenium layer.
  • a metallic backin member or electrode for example of nickel or aluminum
  • a layer of selenium upon one face ofithebacking member and a front electrode, for example of a metal.
  • a front electrode for example of a metal.
  • a metal such as tin, or an alloy, such as oftin, bismuthand cadmium
  • the selenium and the backing member commonly refe'rred to as the secondary barrier, has a direction of rectification opposite to that of the main barrier, that is the one between the selenium and the front electrode.
  • the main barrier that is the one between the selenium and the front electrode.
  • the resistance of the secondary barrier increases substantially. This results in degradation of the performance of such devices, particularly in a substantial increase in the forward resistance.
  • One general object of this invention is to improve the performance characteristics of selenium rectifiers. e i i .lVIore specifically, objects of this invention are to :reduce' the secondary barrier resistance in selenium rectifiers, to minimize variations in this .resistance with time and to realize these de- 11 Claims. (01. its-3'66) siderata concomitantly without the introduction of undesirable properties in-the rectifiers.
  • Another object of this invention is to enable and f cili e. he economic mass production of selenium rectifiers having stable and low secondary; barrier resistance. i
  • a layer or film of tellurium is provided between the selenium layer and the backing member.
  • Such aninterposed layer or film it has been found, results not only in avery low secondary barrier 'resistance but also such a resistance which. is stable with time. Furthermore, rectifiers including such layers are readilyformed and substantially unaffected by atmospheric conditions.
  • a more specific feature of this invention resides in the-method of manufacturinga selenium rectifier which comprises roughing and cleaning an element of a material. suitable for aback electrode, vapor depositing a thin'layer of tellurium on the roughened surface and a layer of selenium on the tellu'rium, in a vacuum, then heat treating the unit to convert the selenium from the amorphous to the crystalline state, mounting a front contact onthe selenium surface, and electrically forming a rectifying barrier between the front contact and the selenium.
  • M Fig. l is a longitudinal section of a vaporizing apparatus suitable, for'practicing a method in accordance with this, invention
  • Fig. 2 is a cross-sectionalview of the apparatus of Fig. 1 taken along the line 2-1;
  • Fig. ,3 is a partial cross-section of t'heapparatus of Fig. 1 taken alongtheline 3-3
  • Fig. 4 is a plot of voltage versus current on a logarithmic scale showing a typical forward characteristic of a nickel-backed selenium unit, andits development during aging, curves A and Aa respectively, the subscript (a) being employed throughout this specificationflto identify the aged characteristics, including the three component resistances which makeup the overall characteristic: the resistance of the ohmic body curve B, the resistanceof the main'barrier, curves C and Ca, and that of the secondary barrier, curves D and De; i h
  • FIG. 5 is a logarithmic plot of voltage versus current to the same scale as the curves of Figs. 4 and showing the forward characteristics and secondary barrier effects of a unit of this invenmeasured characteristic is such as to reducethe forward current at one volt, (the usual operating voltage) from 60 milliamps to milliamps for the particular unit described.
  • the aluminum-selenium units also exhibit a large secondary barrier .loss, curves I and J of Fig. 5, which seriously'irnpairs' the operation of the device.
  • Fig. 7 shows a logarithmic plot of' the overall characteristics and thatof the secondary aluminum-tellurium-selenium barrier of a unit constructed in accordance with this invention and comprising a selenium film having an aluminum backing anda tellurium interlayer before forming curves Mr and Nr, after rormingcurvesM and N, and after aging-Curves M andN and Fig; '8 isa perspective View of a selenium rectifier embo-dying'this invention withpor-tions thereof broken away. 5
  • the front electrode 3 is ofsome material such as an alloy of tin, bismuth and cadmium applied to theunit in intimate contactwith the underlying layer of selenium 4 to'form at the interface between the two the main "rectifying barrier.
  • the secondary rectifying barrier in prior art devices is generally formed between the selenium and the back contact 2. Such barrier is "substantially eliminated inaccordance with this invention by making the layer 5 of tellurium as hereinafter described.
  • the body resistanoe and main barrier components-of the overall resistance have not been included in thesecurvessincethe .body resistance changes very little-andthe-mainbarrier ages in about the same wayas does that for the standard unit showrr in age," Th e secondary barrier characteristic is 'oflower-resistance than for units ho t hayingfihejtel lurium layer, and [it does not changesubstantiallyjm resistance during forming-and aging. r.Ihese; two features result in a composite characteristic z'ivhi'oh' is 'zoflow resistance in the one volt region and which does not exhibit substantial increase inzresist-anceicluring aging.
  • Rectifiers may be constructed in accordance with this invention on a backing member of some suitable material such as nickel, nickel coated iron, aluminum, or magnesium which may be in any. convenient form, for example a disc f or washer.
  • the preliminary step in the treatment of the backing member is to roughen the surface by sandblasting or an equivalent mechanical working so that the selenium layer is provided witha surface to which it will adhere during the subsequent processing and use.
  • the residue from the roughening process is then removed by a preliminary washing after which the backing member is thoroughly cleaned of all dirt and grease.
  • This may be done by dipping the washer in hydrochloric acid for about ten seconds, then washing inwater, dipping in nitric acid for about ten seconds and again washing in water, rinsing in acetone and then rinsing in ether and drying.
  • the backing members may then be degassed and cleaned of residual grease and dirt, if any, by heating them in a vacuum of about millimeters of mercury at 600 or 700 C. for about thirty minutes. All of the foregoing preliminary steps may be performed on a large number of washers at the same time.
  • the cleaned units, washers H in Figs. 1 and 2 of the drawing, are then mounted on a holder, for example, the rack 12 having the spring fingers l3 depending therefrom and engaging the central apertures of the washers I I.
  • the holder l2 and the mounted washers H are then placed within a vacuum chamber 14.
  • the chamber I4 is then sealed by placing the cover I5 thereon with the gasket I6 intermediate the cover and chamber wall. Atmospheric pressure on the exterior of the cover forces it against the end of the chamber wall and compresses the gasket 16 to form an airtight joint when the chamber I4 is evacuated through the exhaust tube 18.
  • a pair of troughs l9 and 20 are attached to the cover l5 and extend along the bottom of the chamber l4 below the mounted discs. These troughs are supported from the cover at one end by metal straps 2
  • the troughs l9 and 20 are filled with the proper amount of tellurium and selenium, respectively, prior to mounting cover I5.
  • a coating of tellurium having a thickness of about 2 milligrams per square inch is vapor deposited on the washers by passing a sufficient current between the terminals 23 and 3
  • the current is removed from the trough l9 and applied to trough 29 to vaporize the selenium therein.
  • the backing washers are sufiiciently spaced from the trough 6 heatersto-remaincool enough to allow condensationof the vaporized metals thereon.
  • The: rate of deposition of the metals should be sufliciently rapid to avoid heating of the-washers and consequently melting of the condensed metals. Since the electrode surface must be relatively rough to retain the selenium layer, the tellurium layer must coat the backing member without smoothing the roughenedsurface, therefore, this layer is only about .0005 "millimeter. in thickness while the layer of deposited selenium must be thick enough to be continuous and present a smooth surface. A selenium layer approximately two mils in thickness has been found satisfactory.
  • the seleniumas deposited is in the amorphous state which is of too high resistance to be practical for use in rectifiers. Therefore, it must be heat treated to convert it to the crystalline form.
  • This treatment comprises a preliminary heating at about 1-10 0. for a period of about four hours in air and then a high temperature treatment also in air for about twenty minutes at a temperature in the range of about 214 C. to 217 C.
  • a front'contact is now provided for each unit by one of well known methods; for example, the contact may be a spray deposited layer of soft metal suchas tin or an alloysuch as one of tin, bismuth and cadmium.
  • Forming of the body is next accomplished by passing current through it in the high resistance direction, from the backing member through the selenium to the soft metal front contact, under progressively increasing voltages up to about 24 volts.
  • the operating characteristics, both initially and over the entire life of a unit constructed in accordance with this invention are considerably better than those of the prior art units as pointed out in the above discussion of the curves of Figs. 4, 5, 6, and '7.
  • the tellurium interlayer enables a wide choice of backing materials to be employed for selenium rectifiers while maintaining a low stable secondary barrier resistance. Further the process of manufacturing these units is amenable to mass production and requires only a minimum of handling of the individual units.
  • An asymmetric conducting device comprising a backing electrode, a thin layer of tellurium thereon, a selenium layer on said tellurium layer, and a front electrode contacting said selenium layer.
  • An asymmetric conducting device comprising a backing electrode having a nickel surface, a thin layer of tellurium thereon, a selenium layer on said tellurium layerand a front electrode contacting the surface of said selenium.
  • An asymmetric conducting device comprising a backing electrode having an aluminum surface, a thin layer of tellurium thereon, a selenium layer on said tellurium layer and a front electrode contacting the surface of said selenium.
  • An asymmetric conducting device comprising a backing electrode having a magnesium surface, a thin layer of tellurium thereon, a selenium layer on said tellurium layer and a front electrode contacting the surface of said selenium.
  • An asymmetric conducting device comprising a backing electrode, a layer of tellurium having a thickness of the order of .005 millimeter thereon, a selenium layer on said tellurium layer, and a front electrode contacting the surface of said selenium.
  • An asymmetric conducting device comprising a backing electrode, a vapor deposited layer of tellurium on a portion of said electrode, a seleni- '7 um layer on said tellurium layer and a front electrode contacting the surface of said selenium.
  • An asymmetric .conducting device comprising a backing electrode, a layer of tellurium thereon,-;a vapor deposited layer of selenium, and a front electrode contacting the surface of said selenium; p I
  • a selenium rectifier unit which comprises rougheni-ng a surface of an electrode element-of suitable metal, cleaning the element, applying a thin coating of tellurium to the roughened surface of said element, coating the tellurium layer with a layer of selenium of sufiicient thickness to have .a relatively smooth external surface, heat treating the unit to conyert the selenium to a crystalline state, applying a front electrode to the selenium surface and electrically forming the unit.
  • the method of making selenium rectifier units that comprisesroughening a surface of each of a plurality of electrode elements of suitable material, vapor depositing tellurium on the roughened surfaces of said cleaned elements in a vacuum, vapor depositing selenium on the tellurium coating surfaces of said elements in a vacuum, the amount of selenium deposited being sufficient to produce a layer that is thick enough to have a relatively smooth external surface, heat treating the units to convert the selenium to the crystalline state, applying front electrodes to the selenium surface and electrically forming the units.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Apparatuses And Processes For Manufacturing Resistors (AREA)
  • Thermistors And Varistors (AREA)
  • Electrodes Of Semiconductors (AREA)
US110684A 1949-08-17 1949-08-17 Selenium rectifier including tellurium and method of making it Expired - Lifetime US2608611A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
NL666602926A NL154007B (nl) 1949-08-17 Inrichting voor bloedgroepbepaling.
BE495728D BE495728A (enrdf_load_stackoverflow) 1949-08-17
NL80468D NL80468C (enrdf_load_stackoverflow) 1949-08-17
US110684A US2608611A (en) 1949-08-17 1949-08-17 Selenium rectifier including tellurium and method of making it
DEW1790A DE919360C (de) 1949-08-17 1950-04-26 Selen-Gleichrichter mit Tellur und Verfahren zu seiner Herstellung
FR1018535D FR1018535A (fr) 1949-08-17 1950-05-17 Perfectionnements aux redresseurs au sélénium et procédé pour leur fabrication
GB20227/50A GB668059A (en) 1949-08-17 1950-08-15 Improvements in asymmetric electrically conducting devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US110684A US2608611A (en) 1949-08-17 1949-08-17 Selenium rectifier including tellurium and method of making it

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US2608611A true US2608611A (en) 1952-08-26

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US110684A Expired - Lifetime US2608611A (en) 1949-08-17 1949-08-17 Selenium rectifier including tellurium and method of making it

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US (1) US2608611A (enrdf_load_stackoverflow)
BE (1) BE495728A (enrdf_load_stackoverflow)
DE (1) DE919360C (enrdf_load_stackoverflow)
FR (1) FR1018535A (enrdf_load_stackoverflow)
GB (1) GB668059A (enrdf_load_stackoverflow)
NL (2) NL80468C (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2739079A (en) * 1952-02-18 1956-03-20 Paul H Keck Method of making photosensitive plates
US2745327A (en) * 1952-05-12 1956-05-15 Haloid Co Electrophotographic process
US2753278A (en) * 1951-04-14 1956-07-03 Haloid Co Method for the production of a xerographic plate
US2758260A (en) * 1952-05-02 1956-08-07 Gen Electric Blocking rectifier circuit
US2803541A (en) * 1953-05-29 1957-08-20 Haloid Co Xerographic plate
US2826725A (en) * 1953-11-10 1958-03-11 Sarkes Tarzian P-n junction rectifier
US2862126A (en) * 1953-08-28 1958-11-25 Zeiss Ikon Ag Radiation sensitive semi-conductive layer of amorphous selenium
US2865794A (en) * 1954-12-01 1958-12-23 Philips Corp Semi-conductor device with telluride containing ohmic contact and method of forming the same
US3473095A (en) * 1965-08-27 1969-10-14 Noranda Mines Ltd Single crystal selenium rectifier

Citations (1)

* 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

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE589126C (de) * 1928-10-30 1933-12-02 Sueddeutsche App Fabrik G M B Verfahren zur Herstellung von elektrischen Ventilplatten durch Auftragen einer Selenschicht auf eine Elektrode
DE512817C (de) * 1928-10-30 1930-11-17 Sueddeutsche Telefon App Kabel Elektrischer Trockengleichrichter
DE519162C (de) * 1928-11-01 1931-02-25 Sueddeutsche Telefon App Kabel Elektrisches Ventil mit zwischen Elektroden angeordneter fester Ventilschicht
DE582343C (de) * 1931-10-10 1933-08-12 Erwin Falkenthal Verfahren zur Herstellung der Halbleiterschicht aus Selen o. dgl. fuer Photo- oder Gleichrichterzellen
AT155590B (de) * 1936-06-22 1939-02-25 Aeg Trockenplattengleichrichter.
BE461938A (enrdf_load_stackoverflow) * 1943-05-13 1900-01-01

Patent Citations (1)

* 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

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2753278A (en) * 1951-04-14 1956-07-03 Haloid Co Method for the production of a xerographic plate
US2739079A (en) * 1952-02-18 1956-03-20 Paul H Keck Method of making photosensitive plates
US2758260A (en) * 1952-05-02 1956-08-07 Gen Electric Blocking rectifier circuit
US2745327A (en) * 1952-05-12 1956-05-15 Haloid Co Electrophotographic process
US2803541A (en) * 1953-05-29 1957-08-20 Haloid Co Xerographic plate
US2862126A (en) * 1953-08-28 1958-11-25 Zeiss Ikon Ag Radiation sensitive semi-conductive layer of amorphous selenium
US2826725A (en) * 1953-11-10 1958-03-11 Sarkes Tarzian P-n junction rectifier
US2865794A (en) * 1954-12-01 1958-12-23 Philips Corp Semi-conductor device with telluride containing ohmic contact and method of forming the same
US3473095A (en) * 1965-08-27 1969-10-14 Noranda Mines Ltd Single crystal selenium rectifier

Also Published As

Publication number Publication date
NL80468C (enrdf_load_stackoverflow) 1900-01-01
BE495728A (enrdf_load_stackoverflow) 1900-01-01
FR1018535A (fr) 1953-01-08
GB668059A (en) 1952-03-12
DE919360C (de) 1954-10-21
NL154007B (nl)

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