지능형 기체센서 제조를 위한 박막공정 연구

Abstract

SnO₂ thin films were prepared on SiO₂/Si substrate by RF-magnetron sputtering method, by post-annealing in order to investigate effects of annealing conditions on electrical properties of SnO₂ thin films. The highest sensitivity to CO gas was observed in SnO₂ in films annealed at 500℃ in air atmosphere. Considering that relatively lower sensitivity and the separation of cauliflower grains was observed in the case of annealing at 700℃ in air atmosphere, we suggest that sensitivity to CO gas might be affected by conduction path of carriers, related with microstructure, as well as conduction carrier concentration. Tin dioxide (SnO₂) thin films were prepared on Si(100) substrate by PE-ALD using the DBDTA((CH₃CO₂)₂Sn[(CH₂)₃CH₃]₂) precursor. The properties were studied as a function of source temperature, substrate temperature, and purging time. Scanning probe microscopic images at the source temperature 50℃ and the substrate temperature 300℃ shows lower roughness than that of 40/60℃ source and 200/400℃ substrate temperature samples. The purging time for optimum process was 8sec and the deposition rate was about 1nm per 10 cycles. The conductance of SnO₂ thin film showed a constant region in the range of 200℃ to 500℃. This thin film deposited for 200 cycle shows better sensitivity to CO gas.