Porous Layer Dopant Storage for Solar Cell Efficiency
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Solution Overview
Problem
Existing solar cell manufacturing methods face challenges in diffusing a sufficient amount of dopant into semiconductor substrates, leading to poor PN junction characteristics due to hydrophobic substrate interactions and high-temperature vaporization issues, which affect productivity and efficiency.
Innovation Solution
A method involving the formation of a porous layer on the semiconductor substrate, using chemical treatments like hydrofluoric acid, to store and diffuse dopants effectively during high-temperature heating, enhancing emitter layer formation and PN junction quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a compound containing dopant is sprayed onto the semiconductor substrate using the spray method, then productivity is improved compared to other methods, but the dopant cannot be formed on the substrate with certainty due to hydrophobic interaction between the hydrophilic compound and hydrophobic substrate
Solution Approach 1:
A porous layer is introduced as an intermediary between the hydrophilic dopant compound and the hydrophobic semiconductor substrate. This porous layer acts as a mediator that facilitates the transfer and retention of the dopant compound on the substrate surface, enabling reliable dopant formation while maintaining the spray method's productivity advantages.
Solution Approach 2:
The invention utilizes a porous layer with specific porous structure to enhance the adsorption and retention of the dopant compound. The porous structure provides increased surface area and capillary action that holds the dopant compound effectively, ensuring reliable dopant formation on the hydrophobic substrate while allowing the spray method to maintain high productivity.
2Manufacturing precision
If high-temperature heating treatment is applied to diffuse the dopant, then the dopant diffuses into the semiconductor substrate, but the dopant compound is vaporized and insufficient dopant remains for diffusion
Solution Approach 1:
The porous layer serves as a dopant reservoir that prevents vaporization loss during high-temperature heating. The porous structure physically retains the dopant compound through capillary forces and surface adsorption, ensuring sufficient dopant remains available for diffusion into the substrate even at elevated temperatures, thereby achieving both good PN junction characteristics and minimizing dopant loss.
Solution Approach 2:
The dopant compound is pre-loaded onto the porous layer before high-temperature heating. This preliminary action ensures that the dopant is already positioned and secured on the porous structure, creating a reservoir that will release dopant gradually during heating without complete vaporization, thus preventing dopant loss while enabling effective diffusion.
3Manufacturing precision
If the porous layer is used to store and diffuse dopants during high-temperature heating, then dopant diffusion is improved and emitter layer formation is enhanced, but an additional step is required to form the porous layer
Solution Approach 1:
The porous layer is designed to perform multiple functions: it acts as a dopant reservoir during heating, provides a template for emitter layer formation, and can potentially serve as part of the final emitter structure. This multi-functionality justifies the additional formation step by eliminating the need for separate dopant storage and emitter formation processes, thereby improving overall manufacturing efficiency despite the added complexity.
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 allows for improved dopant diffusion, simplifies the manufacturing process, and increases solar light utilization efficiency by reducing reflectivity and enhancing PN junction characteristics, thus improving solar cell performance and productivity.
Implementation Method 1
a porous layer which stores the compound having the dopant
Implementation Method 2
the dopant is diffused by a high-temperature heating treatment, thereby forming the emitter layer
Implementation Method 3
a porous layer arranged on the emitter layer to prevent solar light from being reflected
Data Source
AI summary
A solar cell having improved efficiency and its method of manufacture includes: forming a porous layer on a surface of a semiconductor substrate; spraying a compound containing a dopant on the porous layer; and forming an emitter layer on the surface of the semiconductor substrate by diffusing the dopant.