Isolation between vertically stacked nanosheet devices

Abstract

A lower nanosheet stack including alternating layers of a first work function metal and a semiconductor channel material, an upper nanosheet stack including alternating layers of a second work function metal and the semiconductor channel material, one or more dielectric layers between the lower nanosheet stack and the upper nanosheet stack, each separated by an inner spacer. An embodiment where the one or more partial dielectric layers each include an opening. Forming an upper nanosheet stack vertically aligned above an intermediate stack, vertically aligned above a lower nanosheet stack, the upper nanosheet stack, the lower nanosheet stack each including alternating layers of a first sacrificial material and a semiconductor channel material, the intermediate stack including one or more alternating layers of the sacrificial material and a second sacrificial material, recessing the second sacrificial material; and forming second inner spacers where the second sacrificial material was recessed.