NbO2 sintered compact, sputtering target comprising the sintered compact, and method of producing NbO2 sintered compact
View Patent ↗The present invention relates to a NbO 2 sintered compact characterized in that the intensity proportion of the X-ray diffraction peak intensity of a (001) plane or (110) plane of Nb 2 O 5 relative to the X-ray diffraction peak intensity of a (400) plane of NbO 2 is 1% or less. The present invention provides, without using an expensive NbO 2 material, a NbO 2 sintered compact that can be applied to a sputtering target for forming a high-quality variable resistance layer for a ReRAM. In particular, it is an object of the present invention to provide a single phase NbO 2 sintered compact having a high density suitable for stabilizing sputtering.
1. A NbO 2 sintered compact sputtering target, consisting essentially of single phase NbO 2 such that an intensity proportion of an X-ray diffraction peak intensity of a (001) plane or (110) plane of Nb 2 O 5 relative to an X-ray diffraction peak intensity of a (400) plane of NbO 2 is 1% or less, an intensity proportion of an X-ray diffraction peak intensity of a (110) plane of Nb relative to the X-ray diffraction peak intensity of a (400) plane of NbO 2 is 1% or less, and an X-ray diffraction peak intensity of a (400) plane of Nb 12 O 29 relative to the X-ray diffraction peak intensity of a (400) plane of NbO 2 is 5% or less, wherein the sputtering target has a relative density is 95% or more and a surface having a resistivity of 100 mΩ·cm or less.
2. The NbO 2 sintered compact sputtering target according to claim 1 , wherein the density variation between arbitrary two points in a plane of the sintered compact sputtering target is 1.0% or less.
3. The NbO 2 sintered compact sputtering target according to claim 2 , having a diameter of 110 mm or more.
4. The sputtering target according to claim 3 , wherein the sputtering target is bonded to a backing plate made of oxygen-free copper, chromated copper, or zincated copper with an indium solder.
5. A method of producing the NbO 2 sintered compact sputtering target according to claim 1 , comprising the steps of:
mixing a Nb 2 O 5 powder and a Nb powder;
heating the resulting mixture at 1300° C. to 1400° C. in vacuum or in an inert atmosphere to synthesize NbO 2 ;
pulverizing the synthesized NbO 2 ; and
sintering the pulverized powder by hot pressing at 950° C. to less than 1300° C.
6. The method according to claim 5 , wherein the pulverized powder of the synthesized NbO 2 is sintered by hot pressing at 950° C. to 1100° C.
7. The method according to claim 6 , wherein the Nb 2 O 5 powder has a purity of 99.9% or more, and the Nb powder has a purity of 99.9% or more.
8. The method according to claim 7 , wherein the Nb 2 O 5 powder has an orthorhombic or monoclinic crystal system.
9. The method according to claim 5 , wherein the Nb 2 O 5 powder has a purity of 99.9% or more, and the Nb powder has a purity of 99.9% or more.
10. The method according to claim 5 , wherein the Nb 2 O 5 powder has an orthorhombic or monoclinic crystal system.
11. The NbO 2 sintered compact sputtering target according to claim 1 , having a diameter of 110 mm or more.
12. The sputtering target according to claim 11 , wherein the sputtering target is bonded to a backing plate made of oxygen-free copper, chromated copper or zincated copper with an indium solder.
13. The NbO 2 sintered compact sputtering target according to claim 1 , wherein the intensity proportion of an X-ray diffraction peak intensity of the (110) plane of Nb relative to the X-ray diffraction peak intensity of the (400) plane of NbO 2 is 0.1% to 0.4%, and the X-ray diffraction peak intensity of the (400) plane of Nb 12 O 29 relative to the X-ray diffraction peak intensity of the (400) plane of NbO 2 is 1.7% to 4.6%.