Patent ID: 7696455

Claim:
A ceramic heater comprising: a ceramic substrate; a resistive heating element attached to the ceramic substrate; a terminal pad in contact with the resistive heating element; a terminal adapted for electrically connecting the resistive heating element and the terminal pad to a power source; an active brazing material disposed proximate the terminal; and an intermediate layer disposed between the active brazing material and the ceramic substrate and in contact with the terminal pad, the intermediate layer having a variable composition selected from the group consisting of molybdenum/aluminum nitride (Mo/AlN) and tungsten/aluminum nitride (W/AlN) and having a coefficient of thermal expansion between that of the ceramic substrate and that of the active brazing material and having higher mechanical strength and fracture toughness than that of the ceramic substrate to adapt to the ceramic substrate and active brazing material over the range of operating temperatures of the ceramic heater.