Wafer‐Level Manufacturing of MEMS H₂ Sensing Chips Based on Pd Nanoparticles Modified SnO₂ Film Patterns

Abstract

Abstract In this manuscript, a simple method combining atomic layer deposition and magnetron sputtering is developed to fabricate high‐performance Pd/SnO 2 film patterns applied for micro‐electro‐mechanical systems (MEMS) H 2 sensing chips. SnO 2 film is first accurately deposited in the central areas of MEMS micro hotplate arrays by a mask‐assistant method, leading the patterns with wafer‐level high consistency in thickness. The grain size and density of Pd nanoparticles modified on the surface of the SnO 2 film are further regulated to obtain an optimized sensing performance. The resulting MEMS H 2 sensing chips show a wide detection range from 0.5 to 500 ppm, high resolution, and good repeatability. Based on the experiments and density functional theory calculations, a sensing enhancement mechanism is also proposed: a certain amount of Pd nanoparticles modified on the SnO 2 surface could bring stronger H 2 adsorption followed by dissociation, diffusion, and reaction with surface adsorbed oxygen species. Obviously, the method provided here is quite simple and effective for the manufacturing of MEMS H 2 sensing chips with high consistency and optimized performance, which may also find broad applications in other MEMS chip technologies.