Challenges of gate-dielectric scaling, including the vertical replacement-gate MOSFET

The microelectronics revolution has been enabled by the nearly ideal properties of silicon dioxide and its interface with silicon. Continually thinner gate oxides have been a critical feature of the overall scaling of transistor dimensions for three decades, enabling continued speed improvement even as operating voltages decrease. This era of scaling in thickness of a silicon dioxide insulator will soon come to an end, as gate tunneling current, reduced reliability, and diminishing returns in speed make further reductions impossible or unrewarding. New materials systems may provide some relief, but they have yet to show their ability to replace silicon dioxide. Truly novel approaches, such as the Vertical, Replacement Gate process, which provides more current in the same area by increasing the device perimeter, can address the same issues.