GAA Semiconductor Structure With Dielectric Replacement for Wider Channels
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Solution Overview
Problem
The integration of gate-all-around (GAA) devices in semiconductor manufacturing is challenging due to the complexity of fabricating features around the nanowire, which hinders the realization of high-performance and low-power integrated circuits.
Innovation Solution
A method involving a DOI process is used to replace SiGe layers of an active region with dielectric layers, enhancing the effective channel width of nanostructure transistors, and employing a double-patterning or multi-patterning process to form gate-all-around transistors, which improves the performance of SRAM devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fabrication methods are used for GAA devices, then manufacturing process complexity is reduced, but gate control and channel coupling are insufficient
Solution Approach 1:
The fabrication process is divided into multiple patterning steps (double-patterning or multi-patterning) where the gate structure is formed in sequential stages. This segmentation allows precise control over the gate-all-around geometry and nanowire integration while managing process complexity through systematic breakdown of the fabrication sequence
Solution Approach 2:
The gate structure is designed to completely surround the channel region in a nested configuration, with the gate electrode positioned within a gate dielectric layer that encapsulates the nanowire channel. This nested gate-all-around geometry maximizes gate-channel coupling and provides superior control over the channel current
2Productivity
If feature size is scaled down, then production efficiency is improved and costs are lowered, but manufacturing complexity increases
Solution Approach 1:
The method performs preliminary patterning actions to define the gate structure and nanowire positions before final formation steps. By pre-establishing the spatial framework through multiple patterning cycles, the subsequent fabrication steps become more straightforward and less complex, enabling efficient scaling
3Reliability
If gate-all-around structure is implemented, then gate-channel coupling is increased and short-channel effects are reduced, but fabrication around nanowire becomes challenging
Solution Approach 1:
The gate structure transitions from planar two-dimensional control to three-dimensional gate-all-around configuration. This dimensional change enables the gate to wrap completely around the nanowire channel, providing control from all directions and dramatically improving short-channel effects while the systematic fabrication methodology manages the increased manufacturing complexity
Data Source
AI summary
A method for forming a semiconductor structure is provided. The method includes forming a first active region and a second active region. Each of the first active region and the second active region includes first semiconductor layers and second semiconductor layers alternatingly stacked. The method also includes replacing the first semiconductor layers of the second active region with dielectric layers, removing the dielectric layers to form first gaps, removing the first semiconductor layers of the second active region to form first gaps, and forming a first gate stack to fill the first gaps and the second gaps.