Series-parallel multi-layer broadband silicon-based capacitor and preparation method thereof

The invention relates to the technical field of capacitors, and particularly discloses a series-parallel multi-layer broadband silicon-based capacitor and a preparation method thereof, and the method comprises the following steps: selecting a double-sided polished high-conductivity monocrystalline silicon wafer, carrying out the photoetching of a pattern on the front surface of the high-conductivity monocrystalline silicon wafer through step-by-step photoetching, carrying out the etching of developed silicon oxide through ICP gas etching, and carrying out the etching of the developed silicon oxide; the substrate is cleaned, a layer of silicon oxide is grown through a thermal oxidation method, a composite dielectric film of an ONO structure is formed, a layer of polycrystalline silicon film is grown on the substrate through an in-situ doping LPCVD method, reverse side photoetching is carried out, a reverse side electrode leading-out pattern is etched, overlay needs to be carried out on front side photoetching,