Patent ID: 8304701

Claim:
A ceramic heater comprising: a disk-shaped ceramic plate mainly composed of aluminum nitride; a resistive heating element having a unicursal shape, the resistive heating element being buried in the ceramic plate and including molybdenum as a main component and a molybdenum carbide; and a cylindrical shaft having a diameter smaller than an outer diameter of the ceramic plate, the cylindrical shaft being composed of aluminum nitride and joined to a center of the ceramic plate so as to hold the ceramic plate; wherein a molybdenum carbide content in the resistive heating element is higher in a middle portion than in a peripheral portion; and wherein a carbon content of the ceramic plate is higher in a portion in which the middle portion of the resistive heating element is buried than in a portion in which the peripheral portion of the resistive heating element is buried, and the portion in which the middle portion of the resistive heating element is buried is unexposed on a surface of the ceramic plate which is opposite to the surface of the ceramic plate jointed to the cylindrical shaft.