GAA I/O Transistor Gate Stack Layout for Wider Process Windows
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Solution Overview
Problem
Conventional GAA transistors in semiconductor devices face challenges with limited process windows for depositing dipole and metal fill layers due to the presence of high-k dielectric layers, which affects performance and manufacturing costs, especially in I/O device areas with higher operating voltages.
Innovation Solution
Thinning or completely removing the high-k dielectric layer in I/O device areas to create space for dipole and metal gate layers, while maintaining similar process flows for both I/O and core device areas to reduce manufacturing costs and improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick high-k dielectric layer is used in I/O device areas to accommodate higher operating voltages, then voltage tolerance is improved, but spacing between channel members is reduced
Solution Approach 1:
The patent applies different dielectric layer configurations to different device regions: I/O device areas use a thinner high-k dielectric layer to maintain adequate spacing between channel members, while core device areas use a thicker high-k dielectric layer for optimal voltage control. This local differentiation resolves the contradiction by tailoring the dielectric thickness to the specific functional requirements of each region.
2Reliability
If a thick high-k dielectric layer is used in I/O device areas, then voltage tolerance is improved, but process window is reduced
Solution Approach 1:
The patent implements region-specific dielectric layer designs where I/O areas have reduced high-k dielectric thickness compared to core areas. This local quality approach maintains broader process windows in I/O regions by reducing the complexity of depositing and controlling very thin dielectric layers, while still providing adequate voltage tolerance for I/O operations.
3Reliability
If different process flows are used for I/O and core device areas, then performance optimization is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the semiconductor device into distinct I/O device areas and core device areas with different dielectric layer configurations. This segmentation allows independent optimization of each region's performance characteristics while maintaining a unified overall manufacturing process, thereby achieving performance optimization without proportionally increasing manufacturing complexity and cost.
Data Source
AI summary
A semiconductor device according to an embodiment includes a first gate-all-around (GAA) transistor and a second GAA transistor. The first GAA transistor includes a first plurality of channel members, a first interfacial layer over the first plurality of channel members, a first hafnium-containing dielectric layer over the first interfacial layer, and a metal gate electrode layer over the first hafnium-containing dielectric layer. The second GAA transistor includes a second plurality of channel members, a second interfacial layer over the second plurality of channel members, a second hafnium-containing dielectric layer over the second interfacial layer, and the metal gate electrode layer over the second hafnium-containing dielectric layer. A first thickness of the first interfacial layer is greater than a second thickness of the second interfacial layer. A third thickness of the first hafnium-containing dielectric layer is smaller than a fourth thickness of the second hafnium-containing dielectric layer.