US3811002A - Method of manufacturing an electric discharge tube having an electron emitting electrode comprising a cesium-containing layer on a support - Google Patents

Method of manufacturing an electric discharge tube having an electron emitting electrode comprising a cesium-containing layer on a support Download PDF

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Publication number
US3811002A
US3811002A US00280082A US28008272A US3811002A US 3811002 A US3811002 A US 3811002A US 00280082 A US00280082 A US 00280082A US 28008272 A US28008272 A US 28008272A US 3811002 A US3811002 A US 3811002A
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United States
Prior art keywords
cesium
support
electrode
vapor
fluorine
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Expired - Lifetime
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US00280082A
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English (en)
Inventor
S Garbe
P Zalm
W Pastoor
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US Philips Corp
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US Philips Corp
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Priority claimed from DE19712141089 external-priority patent/DE2141089C3/de
Application filed by US Philips Corp filed Critical US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/12—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/32—Secondary emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/34—Photoemissive electrodes

Definitions

  • ABSTRACT A method of manufacturing an electric discharge tube having an electron-emitting electrode comprising a support with a cesium-containing layer thereon which is activated by reaction of a gaseous compound of an inactive or inert gas and fluorine until a cesium fluoride layer having a composition (CsF, Cs) is formed.
  • the gaseous compound at the temperatures prevailing in the tube does not react with the surfaces of other parts.
  • the invention relates to a method of manufacturing an electric discharge tube in which an electronemitting electrode is present which consists of a support on which a cesium-containing layer is provided, which layer is activated by reaction with a gas.
  • the emitting electrode may be a photo-cathode, an injection photocathode, a p-n cathode or a secondary emission electrode.
  • Oxidation also provides an improved photo and secondary emission oncesium present on cesium antimonide (Cs Sb) supports, eitherby vapor-deposition or as an excess in the compound.
  • Cs Sb cesium antimonide
  • Oxidation does not give any improvement of the photoemissionin sodium-potassium antimonide on which cesium is vapor-deposited.
  • the thermal energies of the formation of Na O and K 0, respectively, 100 k.cal/- mol, are so much larger than those of Cs O, 76 k.cal/- mol. that the support is more easily oxidized than the cesium layer.
  • the method according to the invention is preferably carried out with such compounds of fluorine with nitro gen as nitrogen trifluoride NF or with xenon such as xenon difluoride XeF which, at room temperature and already at a pressure of 10- to l0 Torr can convert a monoatomic to 5 atoms thick cesium layer into fluoride in a few minutes to a few seconds without ap preciably reacting with the metal parts or insulators present in the tube, such as the glass wall.
  • oxygen easily reacts with metal surfaces, in particular when they have a porous structure.
  • Thicker cesium layers also react very quickly with the gaseous fluorides.
  • the vapor of a solid fluoride, such as XeF is of course also to be considered as "a gas.
  • photocathodes are also known in which cesium fluoride and still some free cesium is vapordeposited on gallium arsenide or on galliumindium arsenide, until a monoatomic layer is obtained; see S. Garbe, Phys. Stat. Sol. 2, 497 501, 1970.
  • An advantage of such a photocathode is the low work function of the (CsF, Cs) layer of 1.0 eV, associated with a high electron transmission.
  • the stability is also slightly better than that of a'(Cs O, Cs) layer.
  • a difficulty is, however, that the vapor deposition of the cesium fluoride requires a very long evacuation due to the considerable gas supply of the container.
  • the CsF is very hygroscopic.
  • the gas consists of a compound of an inactive or inert gas with fluorine in such a composition that at the temperature occurring in the tube, metal parts and insulators do not flowing system.
  • the (CsF, Cs) layers obtained with the method according to the invention are not less stable than layers in which the CsF is provided by direct vapordeposition.
  • the method according to the invention has the advantage, as compared with the vapor-deposited CsF layers, that all the electrodes obtain a uniform coating. This is particularly important in electron multipliers in which the electrodes are arranged very close together and in which a uniform coating is necessary all the same.
  • the introduction of the gases does not involve impurities as can easily be the case when vapor-depositing fluoride.
  • the method according to the invention may successfully be applied to supports of p-conductive AB" compounds, such as gallium arsenide, which is doped with zinc, silicon or germanium. Also on cesium antimonide (Cs Sb) supports, the improvement of the emission as compared with untreated cesium layers and also as compared with oxidized cesium layers is considerable.
  • Cs Sb cesium antimonide
  • the method is particularly favourable on Na KSb supports on which cesium is vapor-deposited. Although the increase of the photoemission is not so considerable, it is contrasted with the treatment with oxygen which gives no improvement. Perhaps the improvement is to be ascribed to the fact that the formation energies of NaF, KF and CsF are I36, and 127 k.
  • the method according to the invention of the fluorination of an activating emission layer by the treatment of cesium with gaseous fluorides also permits the manufacture of activating layers which consist of mixtures of cesium, fluorine and oxygen. It has proved that the electron emission from such electrodes may be higher than when only one activation layer of (CsF, Cs) or an activation layer of (Cs- O, Cs) alone is present. It is advantageous to perform the method so that first alternatively a few times cesium is vapor-deposited and a fluorination takes place and then a treatmentwith oxygen takes place which may be alternated once or several times with a fluorination of new cesium layers.
  • the support of the activating layer consists of a p-conductive A'B" compound
  • the support in the reaction gas is heated at a high temperature, for gallium arsenide, dependent upon the crystal orientation, at approximately 550 to 600 C.
  • Cesium may then immediately be vapour-deposited and fluorination and oxidation, respectively, be carried out, but better results are obtained when heating is first carried out in a high vacuum.
  • the drawing shows diagrammatically an electron multiplier 1 having a transparent photocathode 2.
  • the multiplier electrodes are denoted by 3. Before the last electrode 3 a grid-like output electrode 4 is present.
  • a grid-like output electrode 4 is present.
  • evaporation sources 5, 6, 7 and 8 for antimony, sodium, cesium and potassium, respectively, are provided.
  • a further cesium source 7 is present.
  • the cathode 2 was formed by vapor-depositing antimony, sodium and potassium, which, when slightly heated, (approximately 180 C) formed the alloy Na KSb.
  • Cesium was deposited on.said alloy simultaneously with the cesium on the gallium phosphide electrodes 3.
  • An acceleration electrode 9 was present between the photocathode 2 and the electrode 3.
  • the improvement of the photoemission by fluorination as compared with the photoemission after oxydation was more than 50 percent. Even better results were obtained when the gallium arsenide was heated in nitrogen trifluoride under a pressure of 2 to 4X 10- 'Torr for 10 minutes at 550 C prior to vapor-depositing the cesium.
  • sensitivities for white light of approximately 700 uA/lumen were obtained by alternate treatment with cesium and oxygen; by alternate treatment with cesium and fluorine to approximately l,000 uA/lumen and by alternate treatment with cesium, fluorine and oxygen even more than 1,100 #A/lumen.
  • the multiplier electrodes consisted of p-silicon with a doping of 5 l()' boron atoms/0cm.
  • the surface of the silicon was purified by a high frequency discharge in argon of 10* Torr. Cesium was then vapor-deposited and fluorinated in the same manner as described above. With an energy of the primary electros of 800 eV, the secondary emission factor was approximately 70. i
  • a method of manufacturing an electric discharge tube having an electron-emitting electrode comprising the steps of providing on a support a cesium-containing layer, and activating said cesium-containing layer by reacting the layer with a gaseous compound of an inactive or inert gas with fluorine at a temperature and pressure at which a cesium fluoride layer ofa composition: (CsF, Cs) is formed without reaction of the gaseous compound with other parts of the tube.
  • reaction gas consists of a compound of fluorine with nitrogen or xenon.
  • reaction gas consists of NE, or XeF 4.
  • reaction is carried our at room temperature at a pressure of between 10- to a few times 10- Torr for a few minutes to a few seconds in flowing gas.
  • reaction gas is incorporated in a carrier gas of a higher pressure.
  • the electron-emitting electrode is a photocathode with a Cs Sb support, an Na KSb support or a p-conductive A'"-B" support.
  • the elec-' trode is an injection electrode, a p-n cathode or a secondary emission electrode.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Cold Cathode And The Manufacture (AREA)
  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Physical Deposition Of Substances That Are Components Of Semiconductor Devices (AREA)
US00280082A 1971-08-17 1972-08-14 Method of manufacturing an electric discharge tube having an electron emitting electrode comprising a cesium-containing layer on a support Expired - Lifetime US3811002A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712141089 DE2141089C3 (de) 1971-08-17 Verfahren zur Herstellung einer elektrischen Entladungsröhre in der eine Elektronen emittierende Elektrode vorhanden ist, welche aus einem Träger besteht, auf dem eine caesiumenthaltende Schicht angeordnet wird

Publications (1)

Publication Number Publication Date
US3811002A true US3811002A (en) 1974-05-14

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US00280082A Expired - Lifetime US3811002A (en) 1971-08-17 1972-08-14 Method of manufacturing an electric discharge tube having an electron emitting electrode comprising a cesium-containing layer on a support

Country Status (5)

Country Link
US (1) US3811002A (ref)
JP (1) JPS52667B2 (ref)
FR (1) FR2149506B1 (ref)
GB (1) GB1362624A (ref)
NL (1) NL160425C (ref)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6648710B2 (en) * 2001-06-12 2003-11-18 Hewlett-Packard Development Company, L.P. Method for low-temperature sharpening of silicon-based field emitter tips

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS563468B2 (ref) * 1974-01-28 1981-01-24
EP0153921A4 (en) * 1983-08-29 1988-05-02 Columbia Chase Corp PHOTOVOLTAIC PRODUCTS AND PROCESS.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3632442A (en) * 1967-04-21 1972-01-04 Philips Corp Photocathodes
US3669735A (en) * 1970-09-04 1972-06-13 Rca Corp Method for activating a semiconductor electron emitter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3632442A (en) * 1967-04-21 1972-01-04 Philips Corp Photocathodes
US3669735A (en) * 1970-09-04 1972-06-13 Rca Corp Method for activating a semiconductor electron emitter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6648710B2 (en) * 2001-06-12 2003-11-18 Hewlett-Packard Development Company, L.P. Method for low-temperature sharpening of silicon-based field emitter tips

Also Published As

Publication number Publication date
DE2141089A1 (de) 1973-02-22
JPS4830364A (ref) 1973-04-21
DE2141089B2 (de) 1976-02-12
FR2149506A1 (ref) 1973-03-30
NL160425C (nl) 1979-10-15
JPS52667B2 (ref) 1977-01-10
NL7211066A (ref) 1973-02-20
GB1362624A (en) 1974-08-07
FR2149506B1 (ref) 1977-04-01
NL160425B (nl) 1979-05-15

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