A method for forming a capacitor structure includes the steps of forming a conductive layer in a substrate, and forming a dielectric layer on the conductive layer opposite the substrate. An aluminum layer is formed on the dielectric layer, and this aluminum layer is patterned so that portions of the dielectric layer are exposed. The patterned aluminum layer is then oxidized to form an alumina masking layer. The alumina masking layer can then be used to selectively etch portions of the dielectric and conductive layers exposed thereby. Related systems are also disclosed.