Preparation and Test of Fe / Cr / Al - Ni / Cr Composite Film Micro - heater

MEMS gas sensor is one of the development directions of the sensor, and it must work at a certain temperature, so micro heater is an important part of MEMS gas sensor. In this paper, aiming at the high cost and complex process of Pt film heater, we developed the research of Fe/Cr/Al and Ni/Cr cheap metals replacing Pt metal. With Fe/Cr/Al and Ni/Cr metal as the targets respectively, Fe/Cr/Al and Fe/Cr/Al-Ni/Cr composite thin film was prepared by DC sputtering on the wafer substrate and was made into micro-heater by wet etching after heat treatment. Finally, the film was characterized by scanning electron microscope (SEM), and the performance of micro heater was test. The characterization indicated that the thickness of film was between 500 nm and 800 nm, the grain size of Fe/Cr/Al was about 40 nm. The test results showed that the change of resistance was small in the range of 0-200 C, so the film suited to be made into micro heater. The relationship between power of micro heater and temperature of chip was linear. The ambient temperature had certain influence on the temperature of chip. In certain DC voltage conditions, when the temperature of chip was 200 C, power consumption of 75 Ω Fe/Cr/Al-Ni/Cr composite film was less than 700 mW, and the heating rate was more than 0.5 C/s. It can satisfy the requirement of MEMS micro gas sensor, which has research value for the substitution of Pt thin film micro heater. Copyright © 2013 IFSA.