Various embodiments of transistor assemblies, integrated circuit devices, and related methods are disclosed herein. In some embodiments, a transistor assembly may include a base layer in which a transistor is disposed, a first metal layer, and a second metal layer disposed between the base layer and the first metal layer. The transistor assembly may also include a capacitor, including a sheet of conductive material with a channel therein, disposed in the base layer or the second metal layer and coupled to a supply line of the transistor. Other embodiments may be disclosed and/or claimed.