Semiconductor structure

Abstract

The invention discloses a semiconductor structure. The semiconductor structure includes several semiconductor stacks over a substrate, and each of the semiconductor stacks extends in a first direction, wherein adjacent semiconductor stacks are spaced apart from each other in a second direction, which is different from the first direction. Each of the semiconductor stacks includes channel layers above the substrate and a gate structure across the channel layers. The channel layers are spaced apart from each other in the third direction which is perpendicular to the first direction and the second direction. The gate structure includes gate dielectric layers around the respective channel layers, and a gate electrode along sidewalls of the gate dielectric layers and a top surface of the uppermost gate dielectric layer. The space in the third direction between the two lowermost channel layers of the channel layers is greater than the space in the third direction between the two uppermost channel layers of the channel layers in the same semiconductor stack. This makes it possible to obtain a more uniform threshold voltage of a nanosheet transistor comprising channel layers in each semiconductor stack.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, in particular to a semiconductor structure. Background technique [0002] In recent years, advanced integrated circuit (IC) devices have become more and more versatile and shrink in size. While scaling down the process generally increases production efficiency and reduces associated costs, it also increases the complexity of handling and manufacturing IC devices. For example, Fin Field-Effect Transistor (FinFET) has been introduced to replace planar transistors. Among these FinFETs, gate-all-around (GAA) structures such as nanosheet metal-oxide-semiconductor field-effect transistors (MOSFETs) have been developed. , to have excellent electrical properties such as improved power performance and area scaling (area reduction) compared to current FinFET technology current. [0003] Although existing semiconductor structures including nanosheet transistors and methods of fabrication t...

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Problems solved by technology

Consequently, the threshold voltage will be different between nanosheet transistors controlled by the same gate stack, which affects the electrical performance of the semiconductor structure during operation.

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