A process for making a capacitor for a silicon-on-insulator (SOI) structure. The SOI structure has a p-type silicon base layer, a buried oxide layer, a silicon layer, and an n+ layer formed within a portion of the p-type silicon base layer. The process comprises the steps of forming a buried oxide layer and a silicon layer in the p-type silicon base layer, forming an n+ layer in a portion of the p-type silicon base layer, and forming electrically conductive paths to the p-type silicon base layer and the n+ layer extending through the buried oxide and silicon layers.