| abstract |
A compact, low electric resistance and high heat-spreading electric circuit substrate, which is suitable for an electric circuit used at microwave of 1 GHz or more as used in the field of wireless communication such as portable telephones or optical communication, is provided. Also provided is a joined body of glass-ceramic with aluminum nitride sintered body, the glass-ceramic containing crystals having the strongest line in the range of 2theta=27.6°-28.2° in powder X-ray diffraction using CuKalpha line, e.g., anorthite crystals, and having a composition containing 0.5-30 mass % of Zn component in terms of oxide, not more than 10 mass % in total of Ti component and Zr component in terms of corresponding oxides and not more than 5 mass % of Pb component in terms of oxide. The joined body is prepared by forming a layer of amorphous glass of above composition on an aluminum nitride sintered body, and thereafter heating the composite at temperatures not lower than the softening point of the amorphous glass, e.g., 600-1100° C., and concurrently crystallizing the same by said heating. |