Multi-head Epitaxial Structure on Semiconductor Fin
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Solution Overview
Problem
The challenge in semiconductor design is to increase the surface area of epitaxial structures on raised semiconductor structures without adding additional epitaxial material, as existing designs face constraints in total height and shape deviations from ideal dimensions, affecting current throughput.
Innovation Solution
A method is developed to fabricate non-planar semiconductor structures with multiple epitaxial heads by growing epitaxial structures on partially recessed top surfaces of raised structures, increasing the surface area through selective removal of epitaxial structure portions and using protective and filler materials to control etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If epitaxial structures are grown on top surfaces of raised semiconductor structures, then current throughput is improved, but the total height of the raised structure with epitaxial structure becomes constrained
Solution Approach 1:
The patent transitions from a single-headed epitaxial structure to a multi-headed epitaxial structure by laterally expanding the epitaxial growth on the raised semiconductor structure. This dimensional change from vertical to lateral expansion increases the effective surface area for current throughput while maintaining the same total height constraint.
Solution Approach 2:
The epitaxial structure is divided into multiple separate heads or regions that are grown on different portions of the raised semiconductor structure. This segmentation allows the total surface area to be increased across multiple discrete regions rather than requiring a single large continuous structure, thereby improving current throughput within height constraints.
2Ease of manufacture
If the raised structures have a tapered shape, then manufacturing is simplified, but the surface area of the epitaxial structure at the tip is reduced
Solution Approach 1:
Instead of trying to increase the tip surface area of a tapered structure (which would require changing the taper geometry and complicating manufacturing), the patent expands the epitaxial structure laterally across multiple heads distributed along the raised structure. This shifts the area increase from the vertical tip dimension to the lateral distribution dimension.
Solution Approach 2:
The epitaxial structure is segmented into multiple heads that can be grown on different sections of the raised structure. This allows the total surface area to be distributed across multiple smaller regions rather than concentrated at the tapered tip, maintaining manufacturing simplicity while increasing functional area.
3Productivity
If additional epitaxial material is added to increase surface area, then current throughput is improved, but the total height constraint is violated
Solution Approach 1:
The patent achieves increased surface area by expanding laterally in the horizontal dimension rather than vertically. Multiple epitaxial heads are distributed across the width and length of the raised structure, converting the area increase strategy from vertical stacking to lateral spreading, thereby avoiding height constraint violations.
Solution Approach 2:
Instead of adding more epitaxial material in a single vertical column, the material is segmented into multiple discrete heads distributed across the raised structure. This segmentation allows the same total amount of epitaxial material to provide greater functional surface area by being spread across multiple locations rather than stacked vertically.
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 enhances current throughput by increasing the surface area of epitaxial structures without adding extra epitaxial material, improving semiconductor performance within existing design constraints.
Implementation Method 1
growing at least one epitaxial structure on a top surface of one or more of the at least one raised semiconductor structure
Data Source
AI summary
A non-planar semiconductor structure includes raised semiconductor structures, e.g., fins, having epitaxial structures grown on top surfaces thereof, for example, epitaxial silicon naturally growing into a diamond shape. The surface area of the epitaxial structure may be increased by removing portion(s) thereof. The removal may create a multi-head (e.g., dual-head) epitaxial structure, together with the neck of the raised structure resembling a Y-shape. Raised structures that are not intended to include an epitaxial structure will be masked during epitaxial structure creation and modification. In addition, in order to have a uniform height, the filler material surrounding the raised structures is recessed around those to receive epitaxial structures.