Silver alloy excellent inreflectance maintenance property

Abstract

The present invention is a silver alloy including silver as the main component and at least one element as a first dopant element higher than silver in melting point, and excellent in reflectance maintenance property. In the present invention, the first dopant element is preferably copper, manganese, silicon, nickel, cobalt, yttrium, iron, scandium, zirconium, niobium, molybdenum, tantalum and tungsten. Also, in the present invention, the silver alloy preferably includes, as a second dopant element, at least one element selected from platinum, gold, rhodium, iridium, ruthenium, palladium, chromium, germanium, indium, tin, lead, aluminum, calcium, gallium, bismuth, antimony, strontium, hafnium, gadolinium, samarium, neodymium, lanthanum, cerium, ytterbium and europium.

1 . A silver alloy for use in a reflective film, comprising silver as a main element and at least one element as a first dopant element higher than silver in melting point.  
   
   
       2 . The silver alloy for use in a reflective film according to  claim 1 , wherein the first dopant element comprises at least one of nickel and molybdenum.  
   
   
       3 . The silver alloy for use in a reflective film according to  claim 1 , wherein the first dopant element comprises at least one of copper, cobalt, titanium, scandium, yttrium, manganese, silicon, iron, zirconium, niobium, tantalum and tungsten.  
   
   
       4 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from gallium, thulium and dysprosium.  
   
   
       5 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from platinum, palladium, magnesium, zinc, terbium, gadolinium and erbium.  
   
   
       6 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from gold, aluminum, neodymium, holmium, tin, bismuth and praseodymium.  
   
   
       7 . The silver alloy for use in a reflective film according to  claim 1 , comprising as a second dopant element at least one element selected from germanium, indium, samarium, ytterbium, strontium, boron, rhodium, iridium, ruthenium, chromium, lead, calcium, antimony, hafnium, lanthanum, cerium and europium.  
   
   
       8 . The silver alloy for use in a reflective film according to  claim 1 , wherein a total of the concentration of the first dopant element and the concentration of the second dopant element are 0.01 to 5.0 atomic %.  
   
   
       9 . The silver alloy for use in a reflective film according to  claim 8 , wherein the total of the concentration of the first dopant element and the concentration of the second dopant element are 0.01 to 3.5 atomic %.  
   
   
       10 . A sputtering target, comprising the silver alloy as defined in  claim 1 .  
   
   
       11 . An optical recording medium comprising a substrate and a silver alloy on the substrate which silver alloy comprises silver and at least one element as a first dopant element having a melting point higher than silver.  
   
   
       12 . The optical recording medium according to  claim 11  wherein the silver alloy comprises a first dopant element comprising at least one of nickel and molybdenum.  
   
   
       13 . The optical recording medium according to  claim 11  wherein the silver alloy comprises a first dopant element comprising at least one of copper, cobalt, titanium, scandium, yttrium, manganese, silicon, iron, zirconium, niobium, tantalum and tungsten.  
   
   
       14 . The optical recording medium according to  claim 11  wherein the silver alloy comprises a second dopant element comprising at least one element selected from gallium, thulium and dysprosium.  
   
   
       15 . The optical recording medium according to  claim 11  wherein the silver alloy comprises a second dopant element comprising at least one element selected from platinum, palladium, magnesium, zinc, terbium, gadolinium and erbium.  
   
   
       16 . The optical recording medium silver according to  claim 11  wherein the silver alloy comprises a second dopant element comprising at least one element selected from gold, aluminum, neodymium, holmium, tin, bismuth and praseodymium.  
   
   
       17 . The optical recording medium according to  claim 11  wherein the silver alloy comprises a second dopant element comprising at least one element selected from germanium, indium, samarium, ytterbium, strontium, boron, rhodium, iridium, ruthenium, chromium, lead, calcium, antimony, hafnium, lanthanum, cerium and europium.  
   
   
       18 . The optical recording medium according to  claim 11  wherein a total of the concentration of the first dopant element and the concentration of the second dopant element in the silver alloy are 0.01 to 5.0 atomic %.  
   
   
       19 . The optical recording medium according to  claim 11  wherein a total of the concentration of the first dopant element and the concentration of the second dopant element in the silver alloy are 0.01 to 3.5 atomic %.  
   
   
       20 . A method for producing an optical recording medium which comprises forming a film of a silver alloy on a substrate, which silver alloy comprises a first dopant element, selected from nickel, molybdenum, copper, cobalt, titanium, scandium, yttrium, manganese, silicon, iron, zirconium, niobium, tantalum, and tungsten, which silver alloy optionally further comprises a second dopant element selected from gallium, thulium, dysprosium, platinum, palladium, magnesium, zinc, terbium, gadolinium, erbium, gold, aluminum, neodymium, holmium, tin, bismuth and praseodymium, germanium, indium, samarium, ytterbium, strontium, boron, rhodium, iridium, ruthenium, chromium, lead, calcium, antimony, hafnium, lanthanum, cerium and europium.