Tri-Layer Semiconductor Stack for Overhang-Free Solar Cell Patterning
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Solution Overview
Problem
Existing solar cell fabrication methods often result in overhang regions during etching processes, which complicate subsequent processing operations and reduce manufacturing efficiency and solar cell efficiency.
Innovation Solution
Implementing a three-layer semiconductor film stack in solar cell manufacturing, where the outermost edge of the third semiconductor layer is laterally recessed from the first semiconductor layer, and the P-type semiconductor layer's edge is sloped, preventing overhang formation and undercutting, thereby improving processing efficiency and solar cell performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional semiconductor layer processing is used, then manufacturing process is simpler, but overhang regions and undercutting occur which complicate subsequent processing
Solution Approach 1:
The semiconductor layer is divided into multiple segments (first, second, and third semiconductor layers) with different lateral extents. This segmentation allows each layer to be patterned independently, preventing overhang and undercutting issues that occur in conventional single-layer processing while maintaining manufacturing feasibility through sequential processing steps.
Solution Approach 2:
The solution transitions from a conventional single-layer two-dimensional patterning approach to a multi-layer three-dimensional structure. By adding the vertical dimension with stacked semiconductor layers having different lateral extents, the patent eliminates overhang and undercutting problems while enabling precise feature patterning through the additional dimensional control.
2Manufacturing precision
If tri-layer semiconductor stack is used, then overhang and undercutting are prevented, but device structure becomes more complex
Solution Approach 1:
The semiconductor structure is segmented into three distinct layers with progressively smaller lateral extents, where each layer serves a specific functional purpose. This segmentation prevents overhang and undercutting while the modular nature of the segmented structure allows for systematic fabrication and reduces overall process complexity despite the increased structural detail.
Solution Approach 2:
The three semiconductor layers are nested within each other with the second layer positioned on the first layer and the third layer positioned on the second layer, creating a compact nested structure. This nesting approach achieves precise patterning and eliminates overhang issues while minimizing the overall device footprint and reducing structural complexity compared to extended lateral configurations.
3Manufacturing precision
If tri-layer semiconductor stack is used, then feature patterning precision is improved, but manufacturing process steps increase
Solution Approach 1:
The first, second, and third semiconductor layers are formed in advance before the final patterning step. This preliminary formation of layered structures with controlled lateral extents allows subsequent patterning operations to achieve high precision without requiring additional complex processing steps, thereby maintaining manufacturing efficiency while improving feature patterning accuracy.
Solution Approach 2:
By utilizing the vertical dimension with stacked semiconductor layers, the patent achieves precise feature patterning through lateral extent control at each layer level. This dimensional approach enables high-precision patterning to be achieved during the layer formation process itself, rather than requiring multiple additional patterning steps that would reduce manufacturing productivity.
Data Source
AI summary
Tri-layer semiconductor stacks for patterning features on solar cells, and the resulting solar cells, are described herein. In an example, a solar cell includes a substrate. A semiconductor structure is disposed above the substrate. The semiconductor structure includes a P-type semiconductor layer disposed directly on a first semiconductor layer. A third semiconductor layer is disposed directly on the P-type semiconductor layer. An outermost edge of the third semiconductor layer is laterally recessed from an outermost edge of the first semiconductor layer by a width. An outermost edge of the P-type semiconductor layer is sloped from the outermost edge of the third semiconductor layer to the outermost edge of the third semiconductor layer. A conductive contact structure is electrically connected to the semiconductor structure.