Process for Production of Ge-Cr Alloy Sputtering Target
A Ge—Cr alloy sputtering target containing 5 to 50 at % of Cr and having a relative density of 95% or more, and a manufacturing method of such a Ge—Cr alloy sputtering target wherein Cr powder having a minus sieve of 75 μm or less, and Ge powder having a minus sieve of 250 μm or less and having a BET specific surface area of 0.4 m 2 /g or less are dispersively mixed in an even manner, and sintered thereafter. Thereby provided is a Ge—Cr alloy sputtering target capable of suppressing variation of the deposition speed and film composition, as well as improving the production yield, of the GeCrN layer deposited with reactive sputtering as the intermediate layer between the recording layer and protective layer of a phase change optical disk, and the manufacturing method of such a target.
1 . A method of manufacturing a Ge—Cr alloy sputtering target, comprising the steps of:
evenly dispersing and mixing Cr powder of 75 μm or less and Ge powder of 250 μm or less, said Ge powder having a BET specific surface area of 0.1 to 0.4 m 2 /g; and
thereafter performing sintering thereto.
2 . A method according to claim 1 , wherein said sintering is performed under conditions of hot pressing at a sintering temperature of 760 to 900° C. and surface pressure of 75 to 250 kg/cm 2 .
3 . A method according to claim 1 , wherein said sputtering target formed by the method contains 5 to 50 at % of Cr, has a relative density of 97% or more and a density variation within ±1.5%, and has in X-ray diffraction a ratio B/A of a maximumn peak intensity A of Ge phase in a 2θ range of 20° to 30° and of a maximum peak intensity B of GeCr compound phase in a 2θ range of 30° to 40° of 0.18 or more.
4 . A method according to claim 3 , wherein a composition variation in the target is within ±0.5%.
5 . A method according to claim 3 , wherein said sintering is performed under conditions of hot pressing at a sintering temperature of 760 to 900° C. and surface pressure of 75 to 250 kg/cm 2 .
6 . A method according to claim 5 , wherein a composition variation in the target is within ±0.5%.