Semiconductor Region Amorphization for Selective FinFET Etching
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Solution Overview
Problem
Existing semiconductor fabrication methods face challenges in efficiently etching and selectively removing semiconductor materials with decreasing device sizes, particularly in non-planar transistor architectures like FinFETs and GAAFETs, leading to device performance degradation and increased complexity.
Innovation Solution
A method involving the implantation of a first semiconductor region with a crystalline structure to amorphize it, followed by etching with a selective etchant, enhances the etch rate and selectivity of the first semiconductor region relative to a second semiconductor region, using materials like silicon and silicon germanium, allowing for precise removal without damaging the second region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching methods are used on crystalline semiconductor regions, then the etching process is simpler, but the etch rate is insufficient and selectivity between different semiconductor regions is poor
Solution Approach 1:
The patent applies preliminary action by implanting ions into the crystalline semiconductor region before etching to amorphize it. This pre-treatment modifies the crystal structure to enable faster and more selective etching in subsequent steps, directly resolving the contradiction between etch rate and selectivity without requiring complex process changes
Solution Approach 2:
The patent changes the physical state parameter of the semiconductor material from crystalline to amorphous through ion implantation. This parameter change enables the etchant to achieve both high etch rate and high selectivity, as amorphous regions etch significantly faster than crystalline regions while maintaining process simplicity
2Productivity
If device size is scaled down to increase functional density, then production efficiency improves and costs decrease, but device performance degradation and fabrication complexity increase
Solution Approach 1:
The patent applies local quality by creating distinct amorphous and crystalline regions within the semiconductor structure through selective ion implantation. This enables differentiated etching behavior in different regions, allowing precise control of feature dimensions at scaled sizes while maintaining device performance and reducing defects
3Manufacturing precision
If selective etching of first semiconductor region over second semiconductor region is achieved through amorphization, then etch selectivity improves, but additional implantation step is required
Solution Approach 1:
The patent uses preliminary action by performing ion implantation to amorphize the first semiconductor region before the etching step. This pre-modification of the material structure enables high etch selectivity in the subsequent etching process, achieving manufacturing precision while the added step remains a straightforward implantation operation
Solution Approach 2:
The patent changes the structural parameter of the semiconductor material from crystalline to amorphous state through ion implantation. This parameter change creates a fundamental difference in etchability between the first and second semiconductor regions, achieving high selectivity that outweighs the addition of the implantation step
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 improves the etch rate and selectivity, facilitating efficient fabrication of non-planar transistors with improved performance and reduced defects, thereby addressing the challenges of scaling down in semiconductor manufacturing.
Implementation Method 1
The first semiconductor region is implanted to form an amorphized semiconductor region
Implementation Method 2
The amorphized semiconductor region is etched with the etchant to remove the amorphized semiconductor region
Data Source
AI summary
A method of fabricating a semiconductor device is described. A substrate is provided. A first semiconductor region of a first semiconductor material is formed over the substrate and adjacent a second semiconductor region of a second semiconductor material. The first and second semiconductor regions are crystalline. An etchant is selective to etch the first semiconductor region over the second semiconductor region. The entire first semiconductor region is implanted to form an amorphized semiconductor region. The amorphized semiconductor region is etched with the etchant using the second semiconductor region as a mask to remove the amorphized semiconductor region without removing the second semiconductor region.