An electronic device includes a first dielectric layer above a semiconductor layer, lower-bandgap dielectric layer above the first dielectric layer, the lower-bandgap dielectric layer having a bandgap energy less than a bandgap energy of the first dielectric layer, a first capacitor plate above the lower-bandgap dielectric layer in a first plane of first and second directions, a second dielectric layer above the first capacitor plate, a second capacitor plate above the second dielectric layer in a second plane of the first and second directions, the first and second capacitor plates spaced apart from one another along a third direction, and a conductive third capacitor plate above the second dielectric layer in the second plane, the third capacitor plate spaced apart from the second capacitor plate in the second plane.