Fabrication and characterization of novel silicon-compatible high-density capacitors

System integration and miniaturization demands are driving component technologies towards integrated thin films with higher volumetric efficiencies and component densities. Among the various system components, achieving higher densities with capacitors, integrated in thin film form has been a major challenge for the past few decades. This paper reports the first proof-of-concept demonstration of a novel silicon-compatible high-density capacitor technology. The key novelty stems from the tremendous enhancement in surface area from thin and porous copper nanoelectrodes and conformal alumina dielectric on such nanoelectrodes. Atomic Layer Deposition was chosen as the dielectric process because of its self-limiting, defect-free and conformal deposition on 3-D structures. Alumina with its moderate permittivity and superior dielectric properties over large voltage ranges was employed as the representative dielectric. Thin copper particulate electrodes with conformal counter electrodes showed 10 times higher capacitance density compared to the planar devices, with similar leakage properties. Thicker electrodes showed enormous enhancement in surface area but inferior leakage properties. Combination of compositional and morphological techniques was used to show alumina conformality on complex 3-D structures of copper particulate electrode. Capacitance–Voltage and Current–Voltage characterizations were carried out to confirm the feasibility of the novel high density 3-D capacitor structure.