Gallium nitride-based sintered compact and method for manufacturing same

Abstract

The object of the present invention is to provide a sputtering target for a gallium nitride thin film, which has a low oxygen content, a high density and a low resistivity. A gallium nitride powder having powder physical properties of a low oxygen content and a high bulk density is used and hot pressing is conducted at high temperature in high vacuum to prepare a gallium nitride sintered body having a low oxygen content, a high density and a low resistivity.

1 . A gallium nitride-based sintered body, which has an oxygen content of at most 1 atm % and a resistivity of at most 1×10 2  Ω·cm. 
     
     
         2 . The gallium nitride-based sintered body according to  claim 1 , which has a density of at least 3.0 g/cm 3  and at most 5.4 g/cm 3 . 
     
     
         3 . The gallium nitride-based sintered body according to  claim 1 , which has an average particle size of at least 0.5 μm and at most 3 μm. 
     
     
         4 . The gallium nitride-based sintered body according to  claim 1 , which has a weight of at least 10 g. 
     
     
         5 . The gallium nitride-based sintered body according to  claim 1 , wherein when it is heat-treated in an air at 250° C. for one hour, there is no visually confirmed deposition of metal gallium from a target member. 
     
     
         6 . A method for producing a gallium nitride-based sintered body by hot pressing, the method comprising:
 heating a gallium nitride powder having an oxygen content of at most 2 atm %, as a raw material at a temperature of at least 1,060° C. and less than 1,300° C. with an ultimate vacuum in a chamber of at most 70 Pa at the time of hot pressing.   
     
     
         7 . A gallium nitride sputtering target, comprising:
 the gallium nitride sintered-based body as defined in  claim 1 .   
     
     
         8 . The gallium nitride sputtering target according to  claim 7 , wherein no layer comprising tungsten is present between a target member and a bonding layer. 
     
     
         9 . The gallium nitride sputtering target according to  claim 7 , wherein a bonding layer comprises at least one component selected from the group consisting of indium, tin and zinc. 
     
     
         10 . A method for producing a gallium nitride-based thin film, the method comprising:
 producing the gallium nitride-based thin film with the gallium nitride sputtering target as defined in  claim 7 .