Research of thick-film capacitive displacement sensors used in nano-meter scaled operation

On the basis of thick-film technology, a novel gap- variation-type thick-film capacitive micro-displacement sensor have been developed to detect nanometer-scaled displacement, using 96% A1₂O₃ ceramic plates and Pd-Ag conducting paste via a print-fire process. This paper describes the principle, structural design and theoretic computation of the capacitive sensor. Factors affecting the sensors´ resolution and linearity, and effects of materials and technological parameters are also discussed. Tests results of the preliminary prototype sensors show that the as-prepared prototype sensors possess good linearity (about 2%, without additional compensation or corrections) and resolution (about 0.025/100 nm). The obtained results demonstrate that the sensors have favorable applied prospects.