Double-Gate Structure Etching via Intermediary Layer
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Solution Overview
Problem
Conventional methods for manufacturing double-gate structures in semiconductor devices often result in device malfunctions and parameter abnormalities due to needle-like gate polysilicon residuals, which are caused by the physical and chemical properties of tungsten silicide, leading to uneven etching and compromised electrical performance.
Innovation Solution
The introduction of an etch-stop layer between the second gate layer and the silicide layer facilitates even etching by controlling the etching process, preventing the formation of needle-like gate polysilicon residuals and ensuring consistent thickness, thereby improving the morphology and electrical performance of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching process is used to form the second gate region, then the etching speed is fast, but needle-like gate polysilicon residuals are formed due to uneven etching
Solution Approach 1:
An etch-stop layer is introduced between the second gate layer and the silicide layer to act as an intermediary that regulates the etching process. This layer ensures uniform etching of the second gate layer around the first gate region while maintaining fast etching speed, preventing the formation of needle-like polysilicon residuals.
2Device complexity
If the silicide layer is formed directly on the second gate layer, then the manufacturing process is simple, but uneven etching occurs around the first gate region
Solution Approach 1:
The etch-stop layer serves as a mediator between the second gate layer and silicide layer, enabling uniform etching control without significantly complicating the manufacturing process. The layer is formed using standard deposition techniques and integrates seamlessly into the existing fabrication flow.
3Manufacturing precision
If the etch-stop layer is arranged between the second gate layer and silicide layer, then even etching is achieved, but an additional layer is added to the structure
Solution Approach 1:
The etch-stop layer is a thin functional layer that provides critical etching control while adding minimal structural complexity. Its primary function is to regulate etching uniformity, and it can be formed using standard thin-film deposition techniques that are already part of the manufacturing process.
Data Source
AI summary
A method is provided for manufacturing a double-gate structure. The method includes providing a substrate and forming a first gate region on a surface of the substrate using a first gate layer. The method also includes forming a second gate layer on the surface of the substrate, wherein the second gate layer covers the first gate region, forming an etch-stop layer on the second gate layer, and forming a silicide layer on the etch-stop layer. The method also includes forming a second gate region, different from the first gate region, containing the second gate layer and the silicide layer without the etch-stop layer. Further, the etch-stop layer is arranged between the second gate layer and the silicide layer to facilitate even etching of the second gate layer around the first gate region.