Metallized aluminum nitride substrate

Patent Granted PROBLEM TO BE SOLVED: To provide a metallized aluminum nitride substrate, wherein the adhesive strength between a metal layer and a substrate is high, and insulation among fine circuit patterns can be obtained surely. ; SOLUTION: The aluminum nitride substrate is heated and oxidized, in an atmosphere in which the partial pressure of oxygen is 10<SP>-4</SP>atmosphere or lower, preferably at 1,150 to 1,500[deg.]C for five hours and longer, to form an aluminum oxide layer of about 3 to 15 [mu]m in thickness, from the surface.