Plate capacitor and preparation method thereof

The invention provides a plate capacitor and a preparation method thereof, and the plate capacitor comprises a lower electrode plate which is doped with silicon and is doped with one of three-group or five-group elements; the adjusting layer is arranged on the outer surface of the lower polar plate, a first through hole is formed in the adjusting layer, and a dielectric medium is contained in the first through hole; the device layer is arranged on the adjusting layer, and a second through hole communicated with the first through hole is formed in the device layer; and the upper polar plate is doped silicon arranged in the second through hole, is doped with one of III-family or V-family elements, and is not in the same family as the doped element of the lower polar plate. According to the plate capacitor disclosed by the invention, the aim of preventing short circuit of the capacitor regardless of positive bias or reverse bias can be fulfilled through the doped elements and the structures of the upper polar pl