Method and evaporation chamber for generating a continuous vapor stream containing a compound having monovalent gallium therein, and a vacuum coating apparatus

Abstract

In a method and evaporation chamber for generating a continuous vapor stream containing a compound in which gallium is present in monovalent form of a vacuum coating method for vacuum coating a substrate, an evaporation substance containing gallium in bivalent or trivalent form, is arranged together with metallic gallium in the evaporation chamber, that is closed on all sides and has a vapor exit opening. The evaporation substance is evaporated, and the vapor is brought into contact with the metallic gallium, causing the bivalent or trivalent gallium to be reduced to monovalent gallium in a vapor stream which subsequently exits in the direction of the substrate via the vapor exit opening.

We claim as our invention:  
     
         1 . A method for generating a continuous vapor stream containing a compound having gallium therein in monovalent form in a vacuum coating procedure for vacuum coating a substrate, comprising the steps of: 
 providing an evacuation chamber which is closed on all sides and which has a vapor stream exit opening;    disposing a multivalent gallium-containing evaporation substance, selected from the group consisting of evaporation substances containing gallium in bivalent form and evaporation substances containing gallium in trivalent form, in said evaporation chamber;    disposing metallic gallium in said evaporation chamber;    evaporating said evaporation substance in said evaporation chamber and thereby generating a vapor which comes into contact with said metallic gallium, for reducing said multivalent gallium to monovalent gallium and causing a continuous vapor stream, containing said monovalent gallium, to exit from said evacuation chamber via said vapor exit opening.    
     
     
         2 . A method as claimed in    claim 1    comprising providing a first level disposed below a second level in said evacuation chamber, and disposing said evaporation substance at said first level in said evacuation chamber and disposing said metallic gallium at said second level in said evacuation chamber, and thereby evaporating said evaporation substance separately from said metallic gallium.  
     
     
         3 . A method as claimed in    claim 2    comprising producing a temperature gradient from 300° C. to 500° C. in said evacuation chamber between said metallic gallium and said evaporation substance.  
     
     
         4 . A method as claimed in    claim 3    comprising producing said temperature gradient from 350° C. to 450° C.  
     
     
         5 . A method as claimed in    claim 3    comprising producing said temperature gradient by cooling said evaporation substance.  
     
     
         6 . A method as claimed in    claim 3    comprising producing said temperature gradient by heating said metallic gallium.  
     
     
         7 . A method as claimed in    claim 1    comprising mixing said evaporation substance with said metallic gallium in said evacuation chamber and evaporating said evaporation substance mixed in said metallic gallium.  
     
     
         8 . A method as claimed in    claim 1    comprising generating a temperature in said evacuation chamber in a range between 250° C. and 950° C. for reducing said multivalent gallium to said monovalent gallium.  
     
     
         9 . A method as claimed in    claim 1    comprising generating a temperature in said evacuation chamber in a range between 300° C. and 900° C. for reducing said multivalent gallium to said monovalent gallium.  
     
     
         10 . A method as claimed in    claim 1    comprising cooling said evaporation chamber in a region surrounding said vapor exit opening.  
     
     
         11 . A method as claimed in    claim 1    comprising providing a vapor exit opening in said evacuation chamber having a diameter in a range between 2 μm and 2 mm.  
     
     
         12 . A method as claimed in    claim 1    comprising providing a vapor exit opening in said evacuation chamber having a diameter in a range between 5 μm and 1.5 mm.  
     
     
         13 . A method as claimed in    claim 1    comprising providing a vapor exit opening in said evacuation chamber having a diameter in a range between 10 μm and 1 mm.  
     
     
         14 . A method as claimed in    claim 1    comprising forming said evaporation chamber of a material which does not react with, and which is not wetted by, said evaporation substance.  
     
     
         15 . A method as claimed in    claim 1    comprising forming said evaporation chamber of a material which does not react with, and which is not wetted by, said metallic gallium.  
     
     
         16 . A method as claimed in    claim 1    comprising forming said evaporation chamber of a material which does not react with, and which is not wetted by, said evaporation substance nor with said metallic gallium.  
     
     
         17 . A method as claimed in    claim 1    comprising forming said evaporation chamber of a material selected from the group consisting of graphite, aluminum oxide and boric nitride.  
     
     
         18 . A method as claimed in    claim 1    comprising selecting said evaporation substance from the group consisting of gallium bromide compounds and gallium indium compounds.  
     
     
         19 . A method as claimed in    claim 1    comprising evaporating a coating material for said substrate in said evacuation chamber at a time selected from the group of times consisting of before evaporation of said evaporation compound, during evaporation of said evaporation compound, and after evaporation of said evaporation compound.  
     
     
         20 . A method as claimed in    claim 19    comprising employing x-ray absorber material as said coating material.  
     
     
         21 . An evacuation chamber for a vacuum coating process comprising: 
 an interior volume for accepting an evaporation substance and at least one additional substance which chemically acts on a vapor produced by said evaporation substance, said volume being closed on all sides and having a vapor exit opening at one side, said vapor exit opening having a diameter of less than 2 mm.    
     
     
         22 . An evaporation chamber as claimed in    claim 21    wherein said vapor exit opening has a diameter of less than 1 mm.  
     
     
         23 . An evaporation chamber as claimed in    claim 1    further comprising a vapor-permeable dividing wall dividing said volume into a lower space for accepting said evaporation substance and an upper space for accepting said additional substance.  
     
     
         24 . An evaporation chamber as claimed in    claim 23    wherein said dividing wall comprises a wire grating.  
     
     
         25 . An evaporation chamber as claimed in    claim 23    wherein said wall comprises a shelf having a plurality of openings therein.  
     
     
         26 . An evaporation chamber as claimed in    claim 23    wherein said dividing wall consists of a material which does not react with, and which is not wetted by, said additional substance.  
     
     
         27 . An evaporation chamber as claimed in    claim 23    wherein said dividing wall consists of a material which does not react with, and which is not wetted by, said vapor.  
     
     
         28 . An evaporation chamber as claimed in    claim 23    wherein said dividing wall consists of a material which does not react with, and which is not wetted by, said additional substance nor said vapor.  
     
     
         29 . An evaporation chamber as claimed in    claim 23    wherein said upper space receives metallic gallium, and wherein said dividing wall comprises a material selected from the group consisting of graphite and aluminum oxide.  
     
     
         30 . An evaporation chamber as claimed in    claim 21    further comprising a heater for heating a region of said volume.  
     
     
         31 . An evaporation chamber as claimed in    claim 30    further comprising a base disposed at a bottom of said volume, and wherein said heater is disposed in said base.  
     
     
         32 . An evaporation chamber as claimed in    claim 30    further comprising a vapor-permeable dividing wall disposed in said volume and dividing said volume into an upper space and a lower space, and wherein said heater is disposed at a region of said dividing wall.  
     
     
         33 . An evaporation chamber as claimed in    claim 21    further comprising a cooling arrangement for cooling a region of said evaporation chamber.  
     
     
         34 . An evaporation chamber as claimed in    claim 33    wherein said cooling arrangement is disposed for cooling an upper region of said evacuation chamber.  
     
     
         35 . An evaporation chamber as claimed in    claim 34    wherein said cooling arrangement is disposed for cooling a region surrounding said vapor exit opening.  
     
     
         36 . An evaporation chamber as claimed in    claim 33    wherein said cooling arrangement is disposed for cooling a lower region of said evaporation chamber.  
     
     
         37 . An evaporation chamber as claimed in    claim 21    comprising a lid-like cover closing said volume and containing said vapor exit opening.  
     
     
         38 . An evaporation chamber as claimed in    claim 21    wherein said walls are comprised of a material selected from the group consisting of graphite, aluminum oxide and boric nitride.  
     
     
         39 . A vacuum coating apparatus comprising: 
 a vacuum chamber containing a substrate to be coated; and    an evaporation chamber disposed in said vacuum chamber, said evaporation chamber containing a multivalent gallium-containing evaporation substance and metallic gallium, and said evaporation chamber having a heater arrangement for evaporating said evaporation substance to produce a vapor which comes into contact in said evaporation chamber with said metallic gallium to reduce said multivalent gallium, said evacuation chamber having a vapor exit opening and being otherwise completely closed so that a vapor stream exits said vapor exit opening in a direction toward said substrate, said vapor stream containing said monovalent gallium.