Field effect transistors including vertically oriented gate electrodes extending inside vertically protruding portions of a substrate

Abstract

A field effect transistor on an active region of a semiconductor substrate includes a vertically protruding thin-body portion of the semiconductor substrate and a vertically oriented gate electrode at least partially inside a cavity defined by opposing sidewalls of the vertically protruding portion of the substrate. The transistor further includes an insulating layer surrounding an upper portion of the vertically oriented gate electrode and a laterally oriented gate electrode on the insulating layer and connected to a top portion of the vertically oriented gate electrode. Accordingly, a T-shaped gate electrode is defined having a lateral portion on a top surface of a semiconductor substrate and having a vertical portion at least partially inside a cavity defined by opposing sidewalls of a vertically protruding portion of the substrate.