U.S. Philips Corporation

Jacobus E Crombeen

Jan Hasker

Jan Visser

Frans M Snijkers

Johannes M Van Esdonk

Pieter Hokkeling

Gary E Thomas

Josef J Van Lith

Anton K Niessen

Petrus A Van Dorst

Henricus J Stoffelen

Petrus W Crooymans

To maintain a monolayer of scandium, which is necessary for a satisfactory emission on the surface of a scandate cathode, at least the top layer of the cathode is provided with a scandium-containing oxidic phase from which Scandium is supplied by segregation of scandium from this oxidic phase.

Scandate cathode and methods of making it

To maintain a monolayer of scandium, which is necessary for a satisfactory emission on the surface of a scandate cathode, at least the top layer of the cathode is provided with a scandium-containing oxidic phase from which Scandium is supplied by segregation from this oxidic phase.

For maintaining a monolayer of scandium which is necessary for a satisfactory emission on the surface of a scandate cathode, at least the top layer of the cathode is provided with scandium coated with a scandium oxide film. Even after repeated ion bombardment the emission is found to recover up to approximately 90% of the initial value at a current density of ca. 100 A/cm.sup.2.

Method of manufacturing scandate cathode with scandium oxide film

By providing at least the top layer of the matrix of a scandate cathode with an alloy or compound which exhibits scandium segregation, a satisfactory recovery for cathodes with a high emission can be achieved after ion bombardment.

Scandate cathode exhibiting scandium segregation

Such a system comprises in an envelope 1 a flat cathode 2 from the material to be sputtered and a substantially circular anode situated coaxially with respect to said cathode. Behind the cathode, magnetic means 13 are provided to generate at least one closed tunnel of field lines 14 over a part of the cathode surface (a so-called electron trap). Between the anode 3 and the edge 8 of the cathode is present according to the invention a coaxial, substantially cylindrical auxiliary electrode 15. From the center of the cathode a rod-shaped auxiliary electrode 16 moreover extends axially. Said auxiliary electrodes 15 and 16 modify the electric field in such a manner that the electrons which are not captured in the tunnel of magnetic field lines are directed substantially towards the anode 3. The distance from the rod-shaped electrode 16 to the substrate 7 must be chosen to be comparatively small. By using the invention the substrate is less heated and not so much damaged by electron bombardment.

Magnetron cathode sputtering system

In a magnetron cathode sputtering system the target (plate of material to be sputtered) 8 is held against a backing plate 13 by a vacuum, enabling the backing plate 13 to be reused. By providing the backing plate with a layer of soldering material which adheres to the backing plate 13, but does not adhere to the target 8, heat transfer between the two plates is improved.

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Eindhoven, Netherlands

Jacobus E Crombeen