Tubular target and production method
A tubular target formed of molybdenum or a molybdenum alloy has an oxygen content of less than 50 μg/g, a density of greater than 99% of the theoretical density, and an average grain size of less than 100 μm. The molybdenum or molybdenum alloy tube may be produced by extrusion. In one embodiment, the molybdenum tube has a backing tube of titanium or titanium alloy. In an embodiment, the molybdenum tube has a varying wall thickness with an increase towards its ends.
1. A tubular target, comprising:
a molybdenum tube formed of a metal powder of Mo or Mo alloy, said molybdenum tube having ends and said molybdenum tube having:
an oxygen content less than 50 μg/g;
a density greater than 99% of a theoretical density; and
an average grain size transversely to an axial direction of said tube of less than 100 μm; and
a supporting tube of titanium or titanium alloy connected to said molybdenum tube and a metallurgical bond connection formed between said molybdenum tube and said supporting tube, said supporting tube reaching beyond the ends of said molybdenum tube.
2. The tubular target according to claim 1 , wherein a contact surface between said molybdenum tube and said supporting tube amounts to at least 30% of a theoretically possible surface area.
3. The tubular target according to claim 1 , wherein said molybdenum tube has an oxygen content of less than 20 μg/g.
4. The tubular target according to claim 1 , wherein said molybdenum tube has a wall thickness that varies over a length of said tube.
5. The tubular target according to claim 1 , wherein said molybdenum tube has a wall thickness increasing towards the ends of said tube.
6. The tubular target according to claim 1 , wherein said molybdenum tube has a density greater than 99.8% of the theoretical density.
7. The tubular target according to claim 1 , wherein said molybdenum tube has an average grain size transversely to the axial direction less than 50 μm.
8. The tubular target according to claim 1 , wherein said molybdenum tube consists of pure molybdenum with a metallic purity, exclusive of tungsten, of greater than 99.99% by weight.
9. The tubular target according to claim 1 , wherein said molybdenum tube consists of a molybdenum alloy containing 0.5 to 30% by weight of at least one of V, Nb, Ta, Cr, and W.
10. The tubular target according to claim 1 , wherein said molybdenum tube has the characteristics of a tube formed by extrusion over a mandrel.
11. The tubular target according to claim 1 , wherein said molybdenum tube has a recovered or recrystallized material structure.
12. The tubular target according to claim 1 , wherein said molybdenum tube is an extruded tube with a degree of forming of 40 to 80%.
13. A deposition process, which comprises:
providing a tubular target according to claim 1 and installing the tubular target in a sputtering deposition system; and
sputtering the tubular target to deposit a molybdenum or molybdenum alloy layer of an LCD-TFT flat screen.
14. A deposition process, which comprises:
providing a tubular target according to claim 1 and installing the tubular target in a deposition system; and
sputtering the tubular target to deposit molybdenum or molybdenum alloy on glass to form a coated glass.