Miniaturized complex transistor devices are formed with reduced leakage and reduced miller capacitance. Embodiments include transistors having reduced capacitance between the gate electrode and source/drain contact, as by utilizing a low-K dielectric constant sidewall spacer material. An embodiment includes forming a gate electrode on a semiconductor substrate, forming a sidewall spacer on the side surfaces of the gate electrode, forming source/drain regions by ion implantation, forming an interlayer dielectric over the gate electrode, sidewall spacers, and substrate, and forming a source/drain contact through the interlayer dielectric. The sidewall spacers and interlayer dielectric are then removed. A dielectric material, such as a low-K dielectric material, is then deposited in the gap between the gate electrode and the source/drain contact so that an air gap is formed, thereby reducing the parasitic “miller” capacitance.