abstract |
There is provided a polycrystalline aluminum nitride substrate that is effective in growing a GaN crystal. The polycrystalline aluminum nitride base material for use as a substrate material for grain growth of GAN-base semiconductors, contains 1 to 10% by weight of a sintering aid component and has a thermal conductivity of not less than 150 W/m·K, the substrate having a surface free from recesses having a maximum diameter of more than 200 μm. |