Integrated spacer for gate/source/drain isolation in a vertical array structure

摘要

Alignment tolerance for a vertical gate transistor device can be relaxed because of a spacer formed adjacent the trench. The gate electrode is formed of two materials that have etch selectivity between them, such that the outer material can be etched a predetermined depth into the recess without etching the inner material, resulting in the formation of a divot at the top of the trench. The divot is filled with an insulating material so that if source drain contacts are misaligned, the spacer serves to insulate the gate electrode from the contacts.