Semiconductor Fin Epitaxy for Threading Dislocation Confinement
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Solution Overview
Problem
The integration of different semiconductor materials, particularly between group III/V and group IV materials, often results in lattice mismatch issues leading to high threading dislocation densities, which can render semiconductor devices unusable due to defects in the crystal structure.
Innovation Solution
A method involving the formation of semiconductor fins through epitaxial growth within trenches on a semiconductor substrate, where the orientation of the epitaxial layer is manipulated using a hard mask to align along specific crystallographic directions, effectively trapping and confining threading dislocations, thereby reducing defect density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If epitaxial growth is performed on a semiconductor substrate with lattice mismatch between group III/V and group IV materials, then different semiconductor materials can be integrated to provide performance benefits, but threading dislocation defects occur due to lattice constant differences
Solution Approach 1:
The patent applies preliminary action by forming a patterned hard mask layer before epitaxial growth to predefine the crystallographic orientation of the epitaxial layer. The hard mask is patterned with specific orientations (e.g., <110> or <100>) that will dictate the growth direction of the epitaxial semiconductor material, ensuring that the layer grows in an orientation that minimizes threading dislocation density before the actual epitaxial growth occurs.
Solution Approach 2:
The patent utilizes parameter changes by controlling the crystallographic orientation parameter of the epitaxial layer through the hard mask pattern. By changing the orientation angle of the hard mask pattern relative to the substrate, the patent optimizes the growth parameters to achieve orientations that reduce lattice mismatch effects and minimize threading dislocation formation during epitaxial growth of mismatched material systems.
2Ease of manufacture
If the epitaxial layer is grown without controlling crystallographic orientation, then the manufacturing process is simpler, but threading dislocation defects increase and device performance deteriorates
Solution Approach 1:
The patent introduces a hard mask layer as an intermediary element that mediates between the substrate and the epitaxial layer. This hard mask serves as a template that controls the crystallographic orientation of the epitaxial growth without requiring complex in-situ orientation control during the growth process itself. The hard mask pattern acts as a sacrificial template that guides the orientation and is later removed, simplifying the overall manufacturing process while achieving precise orientation control.
3Reliability
If hard mask patterning is used to control epitaxial layer orientation, then threading dislocations are confined and defect density reduces, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the epitaxial growth process into distinct stages: first forming and patterning the hard mask layer to define orientation regions, then performing epitaxial growth in those defined regions, and finally removing the hard mask. This segmentation allows for precise control of crystallographic orientation in different areas of the substrate, confining threading dislocations to specific regions while maintaining overall process manageability through clear process stages.
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 the fabrication of semiconductor devices with reduced threading dislocation defects, ensuring a solid structure foundation for improved device performance and reliability.
Implementation Method 1
growing an epitaxial structure in the trench
Data Source
AI summary
A method for manufacturing a semiconductor device is provided. The method includes forming an isolation region on a top surface of a semiconductor substrate; etching a trench in the isolation region, wherein the trench extends along a first direction in a top view; growing an epitaxial structure in the trench; patterning the epitaxial structure to form a semiconductor fin orientated along a second direction in the top view, wherein an angle between the first and second directions is in a range from about 40 degrees to about 50 degrees; and forming a gate structure over the semiconductor fin.