High thermally conductive aluminum nitride sintered product

1. A high thermal conductive aluminum nitride sintered body having:

a thermal conductivity of 220 W/m·K or more; and

a three point bending strength of 250 MPa or more; wherein

a ratio (I Al 2 Y 4 O 9 /I AlN ) of X-ray diffraction intensity (I Al 2 Y 4 O 9 ) of Al 2 Y 4 O 9 (201 plane) with respect to X-ray diffraction intensity (I AlN ) of aluminum nitride (101 plane) that is 0.002 to 0.03, and wherein said aluminum nitride sintered body comprises

0.14-1.5 mass % of Y element and 0.05-0.5 mass % of oxygen,

a mass ratio (O/Y) of oxygen (O) with respect to Y element that is 0.5 or less,

an average diameter of aluminum nitride crystal grains that is 4 μm or more,

a number of crystal grains existing in an arbitrary crystal structure area of 100 μm×100 μm that is 200 or less, and

a maximum diameter of grain boundary phase that is 0.5 μm or less.

2. The high thermal conductive aluminum nitride sintered body according to claim 1 , wherein a ratio (I y 2 O 3 /I AlN ) of X-ray diffraction intensity (I y 2 y 3 ) of Y 2 O 3 (222 plane) with respect to X-ray diffraction intensity (I AlN ) of AlN (101 plane) is 0.002 to 0.06.

3. The high thermal conductive aluminum nitride sintered body according to claim 1 , wherein a minimum diameter of the aluminum nitride crystal grains is 2 μm or more, and a maximum diameter of the aluminum nitride crystal grains is 25 μm or less.

4. The high thermal conductive aluminum nitride sintered body according to claim 1 , wherein a grain boundary phase to be a secondary phase is limited to a phase composed of only 2Y 2 O 3 .Al 2 O 3 .

5. The high thermal conductive aluminum nitride sintered body according to claim 1 , wherein a grain boundary phase to be a secondary phase is limited to a phase consisting of 2Y 2 O 3 .Al 2 O 3 .

6. The high thermal conductive aluminum nitride sintered body according to claim 1 , wherein the mass ratio, O/Y, is 0.4 or less.

7. A high thermal conductive aluminum nitride sintered body having:

a thermal conductivity of 200 W/m·K or more; and

a three point bending strength of 250 MPa or more; wherein

a ratio (I Al 2 Y 4 O 9 /I AlN ) of X-ray diffraction intensity (I Al 2 Y 4 O 9 ) of Al 2 Y 4 O 9 (201 plane) with respect to X-ray diffraction intensity (I AlN ) of AlN (101 plane) is 0.002 to 0.06, and a ratio (I y 2 O 3 /I AlN ) of X-ray diffraction intensity (I y 2 O 3 ) of Y 2 O 3 (222 plane) with respect to X-ray diffraction intensity (I AlN ) of AlN (101 plane) that is 0.008 to 0.06, and wherein said aluminum nitride sintered body comprises

0.14-1.5 mass % of Y element and 0.05-0.5 mass % of oxygen,

a mass ratio (O/Y) of oxygen (O) with respect to Y element that is 0.6 or less,

an average diameter of aluminum nitride crystal grains that is 6 μm or more,

a number of crystal grains existing in an arbitrary crystal structure area of 100 μm×100 μm that is 150 or less, and

a maximum diameter of grain boundary phase that is 0.5 μm or less.

8. The high thermal conductive aluminum nitride sintered body according to claim 7 , wherein a minimum diameter of the aluminum nitride crystal grains is 4 μm or more, and a maximum diameter of the aluminum nitride crystal grains is 25 μm or less.

9. The high thermal conductive aluminum nitride sintered body according to claim 7 , wherein a grain boundary phase to be a secondary phase is limited to either a phase composed of only 2Y 2 O 3 .Al 2 O 3 or a phase composed of only 2Y 2 O 3 .Al 2 O 3 and Y 2 O 3 .

10. The high thermal conductive aluminum nitride sintered body according to claim 7 , wherein a grain boundary phase to be a secondary phase is limited to either a phase consisting of 2Y 2 O 3 .Al 2 O 3 or a phase consisting of 2Y 2 O 3 .Al 2 O 3 and Y 2 O 3 .

11. A semiconductor apparatus comprising the high thermal conductive aluminum nitride sintered body according to claim 1 .

12. A semiconductor apparatus comprising the high thermal conductive aluminum nitride sintered body according to claim 7 .