A low TCR MEMS heater developed for cryogenic application.

A microheater with a small temperature coefficient of resistance (TCR) at liquid hydrogen temperature was designed and fabricated by microfabrication technology. The NiCr heater annealed in N2 at 250 °C achieved the smallest TCR. The crystal structures of the NiCr film annealed in nitrogen were analyzed using a scanning electron microscope (SEM) and by x-ray diffraction (XRD). The crystallization of the NiCr film improved with the increase in annealing temperature. The failure mechanism of the microheater is studied, and it is seen that the central area of the heating film and the joint of the heating film and the electrode are most vulnerable to destruction. [ABSTRACT FROM AUTHOR]