| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a heater having a superior thermal response characteristic and a high durability by integrally arranging an exothermic resistor on a high thermal-conductivity silicon nitride substrate, in which a crystalline compound phase is contained in a grain boundary phase at a specific volumetric ratio and which has porosity, a three-point bending strength, and thermal conductivity which respectively fall within specific ranges. SOLUTION: A high thermal-conductivity silicon nitride substrate 11 which is composed of silicon nitride particles and a grain boundary phase, in which a crystal compound phase is contained at a volumetric ratio of about 20% or higher with respect to the overall volume of the grain boundary phase and has a porosity of about 1.5 vol.% or lower, a three-point bending strength of about 80 kg/mm<2> or higher, and thermal conductivity of about 60 W/m.K or higher, is used for a heater. The heater is obtained by forming an exothermic resistor 12 composed of tantalum nitride on the surface of the substrate 11, and an insulating layer 13 is formed integrally on the surface of the substrate 11 so as to cover a resistor 12. Therefore, the heater can exhibit superior thermal response characteristic with respect to the turning on/off of a voltage applied across the resistor 12 and, in addition, has high durability.</p> |
