We have fabricated a Si metal‐oxide‐semiconductor field‐effect transistor with a 20‐nm channel length using a novel step/edge technique. An Al gate is evaporated onto a step in the SiO2gate oxide. A second Al gate, separated from the first by a plasma‐enhanced chemical‐vapor‐deposited SiO2layer, provides inversion layer extensions of the source and drain contacts. Electrical conductance measurements indicate a channel length approximately equal to the fabricated gate length.