Back-Contact Solar Cell Rear Patterning Without Photolithography
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Solution Overview
Problem
Conventional back contact solar cells face efficiency issues due to shadowing effects and require complex photolithography processes, increasing fabrication costs and time.
Innovation Solution
A fabrication method using a laser to form patterns for p-type and n-type semiconductor regions on the rear surface of the back contact solar cell, eliminating the need for photolithography and simplifying the process while reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to form patterns for p-type and n-type semiconductor regions, then manufacturing precision is improved, but device complexity and fabrication cost increase
Solution Approach 1:
The patent replaces the photolithography process (which requires photoresist coating, exposure, and development steps) with a direct laser writing method. The laser directly writes the pattern for p-type and n-type semiconductor regions on the rear surface without requiring photolithography masks or photoresist processing, thereby simplifying the fabrication process while maintaining pattern formation precision.
2Manufacturing precision
If photolithography process is used to form patterns, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The patent extracts and removes the photolithography steps (photoresist coating, exposure, development) from the fabrication process. By using direct laser writing to form the patterns for p-type and n-type semiconductor regions, the time-consuming photolithography sequence is eliminated while still achieving the required pattern precision.
3Reliability
If front electrodes are formed on light-receiving face to extract current, then electrical conductivity is improved, but shadowing effect increases reducing efficiency
Solution Approach 1:
The patent inverts the conventional electrode placement strategy by moving all electrodes (both front and rear contacts) to the rear surface of the solar cell. This inversion eliminates the shadowing effect on the light-receiving face while maintaining electrical conductivity through the formation of p-type and n-type semiconductor regions with appropriate contact structures on the rear surface.
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 method enhances efficiency by minimizing shadowing and reducing electron-hole pair recombination, while simplifying the fabrication process and lowering costs.
Implementation Method 1
removing the oxide layer by irradiating laser light to the oxide layer formed on the rear surface of the substrate at predetermined intervals to form a pattern of the different conductive type semiconductor regions
Implementation Method 2
The solar cell, which is a device converting light energy into electrical energy using a photovoltaic effect
Data Source
AI summary
The present invention discloses a back contact solar cell comprising: a first conductive type semiconductor substrate having a front surface and a rear surface of a texturing structure; an oxide layer formed on the front surface of the substrate; at least one first conductive type semiconductor region and second conductive type semiconductor region alternatively formed at predetermined intervals on the rear surface of the substrate; an oxide layer formed on the remaining rear surface of the substrate except for the first conductive type semiconductor region and the second conductive type semiconductor region; and electrodes formed on each of the first conductive type semiconductor region and the second conductive type semiconductor region.