Fully isolated thin-film trench capacitor

摘要

A process for forming an isolated thin-film trench capacitor includes forming a first trench in a substrate and filling it with an electrically insulating material. A trench capacitor is formed in the first trench by forming first and second pluralities of conductive plates, such as polycrystalline silicon, separated by a layer of dielectric material. The first plurality of conductive plates are electrically connected together and the second plurality of conductive plates are electrically connected together. The dielectric material isolates the trench capacitor from the remainder of the chip. In one form, the trench capacitor comprises a plurality of second trenches in the electrically insulating material and the plurality of conductive plates are formed in the second trenches. In another form, a second trench is formed in the electrically insulating material and the trench capacitor is formed by interleaving conductive layers separated by dielectric material in the second trench.