Extended Active Regions via Epitaxial Growth
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Solution Overview
Problem
Conventional semiconductor processing technologies impose rigid dimensional constraints on active regions, limiting design flexibility and preventing the formation of wider active regions that could enhance drive current, as they require increased cell size for wider regions.
Innovation Solution
A method involving the formation of trenches adjacent to active areas, filling with insulating material, creating recesses, and growing epitaxial regions within these recesses to extend active areas while maintaining compliance with existing dimensional constraints, allowing for both standard and high drive current devices within the same integrated circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If wider active regions are formed to increase drive current, then transistor drive current is improved, but cell size increases
Solution Approach 1:
The patent extends the active region in the vertical dimension by growing epitaxial semiconductor material into recesses formed in the substrate. This allows the active region width to be increased without proportionally increasing the lateral cell area, as the extension occurs downward into the substrate rather than outward laterally.
Solution Approach 2:
The patent segments the active region formation into multiple parts: the original active region at the surface and extended active regions formed by epitaxial growth in recesses. This segmentation allows the active region to be extended vertically while maintaining compact lateral dimensions, thus increasing drive current without increasing cell size.
2Manufacturing precision
If dimensional constraints are imposed to ensure manufacturing tolerances and device isolation, then manufacturing precision is improved, but design flexibility is reduced
Solution Approach 1:
By extending active regions vertically into recesses rather than laterally at the surface, the patent maintains compliance with lateral dimensional constraints while achieving variable active region widths. This allows different active region configurations within the same cell pitch, enhancing design flexibility without violating manufacturing dimensional constraints.
Solution Approach 2:
The patent applies local quality by forming extended active regions only in specific locations where additional drive current is needed, while other regions maintain standard active region widths. The epitaxial growth is selectively performed in certain recesses to create high drive current devices, while adjacent regions maintain standard characteristics, allowing mixed device types within the same integrated circuit.
3Ease of manufacture
If standard active region widths are used to comply with design rules, then ease of manufacture is improved, but drive current capability is limited
Solution Approach 1:
The patent achieves extended active region widths that exceed standard design rule limits by growing epitaxial material vertically into recesses. This vertical extension method allows the active region width to be effectively increased without violating lateral design rule constraints, thereby enabling higher drive current capability while maintaining ease of manufacture through compliance with existing design rules.
Solution Approach 2:
The patent changes the physical state and dimensions of the active region by growing epitaxial semiconductor material in recesses. This parameter change allows the active region width to be extended beyond conventional limits defined by design rules, as the measurement and constraint application remain at the surface level while the functional active region extends deeper into the substrate.
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 increases design flexibility and enhances transistor drive current by widening active regions without compromising manufacturing tolerances or device isolation, achieving extended active regions that comply with existing semiconductor processing technologies.
Implementation Method 1
growing a first epitaxial region in the first recess to extend the first active area to include the first recess
Data Source
AI summary
A method of making a semiconductor device is achieved in and over a semiconductor layer. A trench is formed adjacent to a first active area. The trench is filled with insulating material. A masking feature is formed over a center portion of the trench to expose a first side of the trench between a first side of the masking feature and the first active area. A step of etching into the first side of the trench leaves a first recess in the trench. A first epitaxial region is grown in the first recess to extend the first active area to include the first recess and thereby form an extended first active region.