Study on sputtering yield of tungsten with different particle sizes: Surface roughness dependence

Abstract

The sputtering yield of tungsten pellets composed of different particle sizes of <1, 12, 44–74, and 149–297 μm was systematically investigated by bombardment with Ar+ ions accelerated at 2.0 keV in an ultra-high vacuum chamber. We found that the tungsten sample fabricated from larger particles had a higher surface roughness, based on the surface profile results. Using the data of the surface roughness for the four types of tungsten pellets, we confirmed that the sputtering yield for a tungsten pellet with the highest surface roughness was 7 times lower than that of the lowest surface roughness. This could be due to the redeposition of sputtered tungsten particles onto neighboring asperities.

Keywords

• Tungsten
• Sputtering yield
• Surface roughness
• Fusion power
• Divertor