SnO₂ gas sensors using LTCC (Low temperature Co-fired ceramics)

A sensor element array for combinatorial solution deposition research was fabricated using LTCC (Low-temperature Co-fired Ceramics). The designed LTCC was co-fired at 800°C for 1 hour after lamination at 70°C under 3000 psi for 30 minutes. SnO₂ sol was prepared by a hydrothermal method at 200°C for 3 hours. Tin chloride and ammonium carbonate were used as raw materials and the ammonia solution was added to a Teflon jar. 20 droplets of SnO₂ sol were deposited onto a LTCC sensor element and this was heat treated at 600°C for 5 hours. The gas sensitivity (S = R_a/R_g) values of the SnO₂ sensor and 0.04 wt% Pd-added SnO₂ sensor were measured. The 0.04 wt% Pd-added SnO₂ sensor showed higher sensitivity (S = 8.1) compared to the SnO₂ sensor (S = 5.95) to 200 ppm CH₃COCH₃ at 400°C.