Methods of forming semiconductor devices with extended active regions

Abstract

A method of forming a semiconductor device can include forming a trench in a semiconductor substrate to define an active region. The trench is filled with a first device isolation layer. A portion of the first device isolation layer is etched to recess a top surface of the first device isolation layer below an adjacent top surface of the active region of the semiconductor substrate and to partially expose a sidewall of the active region. The exposed sidewall of the active region is epitaxially grown to form an extension portion of the active region that extends partially across the top surface of the first device isolation layer in the trench. A second device isolation layer is formed on the recessed first device isolation layer in the trench. The second device isolation layer is etched to expose a top surface of the extension portion of the active region and leave a portion of the second device isolation layer between extension portions of active regions on opposite sides of the trench. An interlayer dielectric is formed on the semiconductor substrate and the second device isolation layer. A conductive contact is formed extending through the interlayer dielectric layer and directly contacting at least a portion of both the active region and the extension portion of the active region overlying the second device isolation layer.