Smart digital micro-capacitor based on doped nanocrystalline silicon with HFO2 high K insulator

A digital variable capacitor has been designed and fabricated based on multi-cantilevers of doped nanocrystalline silicon with variable lengths, suspended over a bottom electrode on top of a high-k material, HfO
₂
, to increase the tuning range of the capacitance. By applying a voltage between the electrodes, the electrostatic force pulls the beams in one-by-one, realizing a digital increase in capacitance. These devices were fabricated using a 4-mask process, and electrical tests confirmed the stepwise increase of the capacitance with voltage from the multi-cantilever digital capacitors.