Methods for forming double gate electrodes using tunnel and trench

摘要

A double gate electrode for a field effect transistor is fabricated by forming in a substrate, a trench and a tunnel that extends from a sidewall of the trench parallel to the substrate. An insulating coating is formed inside the tunnel. A bottom gate electrode is formed within the insulating coating inside the tunnel. An insulating layer is formed on the substrate and a top gate electrode is formed on the insulating layer opposite the bottom gate electrode.