Characterization of Heating Elements with Cobalt Silicide Films for InkJet Printer

摘要

The back shot type inkjet printing head was designed and fabricated using cobalt silicide films as a heating element. The cobalt silicide films were prepared on poly-Si/SiO_2/Si substrates by Co metal deposition using the e-beam evaporation and the rapid thermal annealing process. The stable CoSi_2 phase with a sheet resistance of 1.7 Ω/γ was obtained at 800 ℃ for 20 seconds under N_2 atmosphere. From the FE-SEM morphology, the film structure (thickness of each layer) of the heating element was found to be PE-oxide/CoSi_2 (580oA)/Poly-Si (6200A)/SiO_2 on Si substrate. The temperature resistance coefficient of the heating element was calculated by about 0.0014 ℃~~(-1). The resistance was decreased slightly with increasing the input voltage from 2V to 10V, and showed constant values with 38 Ω at above 11V. The breakdown voltage was 19V. There was no distinct change in the resistances of heating elements after 10~8 pulse cycles at the input voltage of 11V and 15V. In addition, the ink. bubbles were observed clearly around the inkjet heater, which was operated at the input voltage of 15V.