Semiconductor Gate Structures With Post-Growth Spacer Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in maintaining the integrity of dummy gate structures during the transition to active gate structures, leading to potential collapse and undesired epitaxial growth, which affects the critical dimensions and material selection of gate spacers.
Innovation Solution
The method involves forming a dummy gate structure over semiconductor layers that are unfavorable for epitaxial growth, followed by the formation of a gate spacer after source/drain structures, allowing for the removal of the dummy gate structure and subsequent formation of an active gate structure that wraps around the channel layers, thereby reducing the risk of collapse and enabling precise control over gate spacer material selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dummy gate structure is formed early in the manufacturing process, then the gate structure can be established as a reference for subsequent processing, but the dummy gate structure may collapse during later processing steps affecting critical dimensions
Solution Approach 1:
The dummy gate structure is formed early in the manufacturing process before source/drain structures are created. This preliminary gate structure serves as a reference for subsequent processing steps, allowing precise definition of gate critical dimensions that are maintained throughout the manufacturing process.
Solution Approach 2:
The dummy gate structure acts as an intermediary element that is eventually replaced by the active gate structure. It provides the necessary structural reference during manufacturing but is removed once its purpose is fulfilled, preventing it from causing harmful effects in later stages.
2Manufacturing precision
If source/drain structures are formed before the gate spacer, then the gate structure can be established, but undesired epitaxial growth may occur on the gate spacer
Solution Approach 1:
The gate spacer is formed after the source/drain structures are in place, allowing the spacer to be precisely positioned relative to the gate structure. This sequencing ensures that the spacer material is deposited on surfaces that have already been prepared, preventing undesired epitaxial growth.
Solution Approach 2:
The manufacturing process changes the state of the gate spacer formation by delaying it until after source/drain structures are complete. This parameter change in process sequencing prevents the harmful epitaxial growth that would occur if the spacer were formed earlier on unprepared surfaces.
3Productivity
If the dummy gate structure is removed early, then the gate trench is available for active gate formation, but the structural support is lost leading to potential collapse
Solution Approach 1:
The dummy gate structure is maintained throughout the manufacturing process to provide structural support and define critical dimensions. It is removed only after it has fulfilled its purpose as a reference structure, at which point the active gate structure is already in place to provide the necessary structural support.
Solution Approach 2:
The dummy gate structure is discarded after its preliminary function is complete, but its removal is timed to coincide with the formation of the active gate structure. This ensures that structural support is continuously maintained throughout the process, with the active gate recovering the support function once formed.
Data Source
AI summary
A method for fabricating a semiconductor device is provided. The method includes forming a fin structure extending along a first lateral direction; forming a dummy gate structure that is over a portion of the fin structure and extends along a second direction perpendicular to the first lateral direction; growing source/drain structures that are respectively coupled to ends of the portion of the fin structure; removing the dummy gate structure to form a gate trench; lining inner sidewalls of the gate trench with a gate spacer; and forming an active gate structure in the gate trench.