Self-Aligned Gate Endcap Layout With HfO2 Cap for Tighter Spacing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The scaling of multi-gate transistors in semiconductor devices faces challenges due to constraints in lithographic processes, particularly in achieving optimal spacing and dimensions, leading to increased gate capacitance and energy consumption, which degrades performance.
Innovation Solution
The implementation of self-aligned gate endcap (SAGE) architectures with monoclinic doped hafnium oxide (HfO2) as an etch-resistant protective layer, allowing for reduced gate endcap overlap and diffusion spacing without the need for mask registration, and using a disposable spacer to determine gate and trench contact overlap dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithographic processes are used to pattern multi-gate transistors, then manufacturing simplicity is maintained, but the spacing between features and critical dimensions are constrained, leading to increased gate capacitance and energy consumption
Solution Approach 1:
The gate endcap structure is formed in advance during the transistor fabrication process, creating a physical barrier that pre-defines the minimum spacing between adjacent transistors. This preliminary structural provision eliminates the need for larger spacing margins typically required by lithographic process variations, enabling tighter feature spacing and reduced gate capacitance without compromising manufacturing yield.
2Reliability
If larger gate endcap overlap is used to account for mask mis-registration, then manufacturing reliability is improved, but device area increases and layout density decreases
Solution Approach 1:
The gate endcap structure serves a dual function: it acts as both the functional gate electrode and a self-aligned spacing definition feature. The endcap's physical presence automatically establishes the minimum spacing between adjacent transistors without requiring additional margin for mask mis-registration, as the structure itself becomes the reference feature for subsequent patterning steps.
3Productivity
If tighter spacing between transistors is implemented, then layout density is improved, but lithographic process constraints are exceeded, making fabrication difficult
Solution Approach 1:
The gate structure is segmented into a functional gate region and an endcap region, with the endcap serving as a dedicated spacing definition element. This segmentation allows the critical dimension control to be localized to the endcap feature rather than requiring the entire gate structure to meet tight dimensional tolerances, thereby simplifying the lithographic patterning process while enabling higher layout density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables more aggressive diffusion spacing, reduces device variability, and improves electrical parameters by eliminating the need for extra endcap length to account for mask mis-registration, thereby enhancing transistor layout density and performance.
Implementation Method 1
monoclinic doped hafnium oxide (HfO2) as an etch-resistant protective layer
Data Source
AI summary
Self-aligned gate endcap (SAGE) architectures with improved caps, and methods of fabricating self-aligned gate endcap (SAGE) architectures with improved caps, are described. In an example, an integrated circuit structure includes a first gate structure over a first semiconductor fin. A second gate structure is over a second semiconductor fin. A gate endcap isolation structure is between the first gate structure and the second gate structure. The gate endcap isolation structure has a higher-k dielectric cap layer on a lower-k dielectric wall. The higher-k dielectric cap layer includes hafnium and oxygen and has 70% or greater monoclinic crystallinity.