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% Al2O3 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.