3d-stacked semiconductor device having different channel and gate dimensions across lower stack and upper stack

Abstract

Provided is a multi-stack semiconductor device including: a substrate; a lower-stack nanosheet transistor including two or more lower channel layers surrounded by a lower gate structure, the lower channel layers connecting lower source/drain regions; and an upper-stack nanosheet transistor formed above the lower-stack nanosheet transistor, and including two or more upper channel layers surrounded by an upper gate structure, the upper channel layers connecting upper source/drain regions, wherein the lower-stack nanosheet transistor and the upper-stack nanosheet transistor have at least one of: a difference between a thickness of one of the lower channel layers and a thickness of one of the upper channel layers; and a difference between a thickness of the lower gate structure between two adjacent lower channel layers and a thickness of the upper gate structure between two adjacent upper channel layers.