Thermally conductive, electrically insulating material and production method thereof

Abstract

Means for a thermally conductive and electrically insulating material containing an AlN crystal mainly comprising AlN, and a production method thereof. In production, a molten aluminum layer is formed on an AlN substrate with at least its surface comprising AlN in an atmosphere of a non-oxidizing gas, and the molten aluminum layer is then heated in an atmosphere of N 2 gas to form an AlN crystal which mainly comprises an AlN layer. The means are also a thermally conductive and electrically insulating material having an AlN crystal and an Al gradient layer, and a production method thereof. In production, a heating step of forming a molten aluminum layer on the AlN layer and heating it in an atmosphere of N 2 gas is repeated at least twice or more. At this time, the amount of the N 2 gas dissolved in the molten aluminum layer is decreased as the heating step is repeated.

1 . A method for producing a thermally conductive and electrically insulating material containing an aluminum nitride (AlN) crystal which comprises an AlN layer mainly comprising AlN, wherein the method comprising:
 forming a molten aluminum layer on an AlN substrate with at least a surface thereof comprising AlN in an atmosphere of non-oxidizing gas in which vaporized magnesium is contained, and   heating said molten aluminum layer in an atmosphere of N 2  gas to form an AlN crystal which comprises an AlN layer mainly comprising AlN.   
     
     
         2 . The method for producing a thermally conductive and electrically insulating material according to  claim 1 , wherein said vaporized magnesium is included in said atmosphere of non-oxidizing gas in said heating step. 
     
     
         3 . The method for producing a thermally conductive and electrically insulating material according to  claim 1 , wherein in said forming step, said magnesium is vaporized by heating metallic magnesium, and is dispersed into said atmosphere of non-oxidizing gas. 
     
     
         4 . The method for producing a thermally conductive and electrically insulating material according to  claim 3 , wherein said metallic magnesium is plate-like or pellet-like magnesium. 
     
     
         5 . The method for producing a thermally conductive and electrically insulating material according to  claim 1 , wherein in said forming step, said magnesium is vaporized by heating a magnesium-containing aluminum alloy, and is dispersed into said atmosphere of non-oxidizing gas. 
     
     
         6 . The method for producing a thermally conductive and electrically insulating material according to  claim 5 , wherein said magnesium-containing aluminum alloy is in the form of a sheet.