Solar Cell Emitter Formation via Laser Doping and Epitaxial Deposition
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Solution Overview
Problem
Current solar cell fabrication processes are inefficient and costly, particularly in implementing high-efficiency crystalline silicon emitter regions on thin epitaxial silicon structures, which require long and expensive process operations.
Innovation Solution
The method involves forming multiple silicon layers and a phosphosilicate glass layer on a template substrate within an epitaxial deposition chamber, followed by laser doping to drive phosphorous dopants into the emitter regions, allowing for a trenchless architecture with high efficiency and reduced process duration, thereby simplifying the fabrication of solar cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication processes are used to implement crystalline silicon emitter regions on thin epitaxial silicon structures, then manufacturing precision and emitter quality are improved, but process duration and manufacturing cost increase significantly
Solution Approach 1:
The patent replaces conventional mechanical/chemical fabrication processes with a laser-based system. A laser beam is used to directly write and form crystalline silicon emitter regions by melting and rapidly cooling the thin epitaxial silicon layer, substituting traditional multi-step mechanical deposition and doping processes with a single laser writing operation that achieves precise emitter formation without prolonged process duration
Solution Approach 2:
The patent utilizes controlled changes in thermal parameters through laser irradiation. By precisely controlling laser power, scanning speed, and pulse duration, the process transforms the thermal state of the silicon material to form high-quality crystalline emitter regions. The rapid heating and cooling cycles create the necessary conditions for crystalline structure formation without requiring long process times
2Manufacturing precision
If conventional fabrication processes are used to implement crystalline silicon emitter regions on thin epitaxial silicon structures, then emitter quality is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple conventional fabrication steps into a single laser writing operation. The laser process simultaneously achieves material melting, crystallization, doping, and emitter region formation that traditionally required separate deposition, annealing, and doping steps, thereby reducing manufacturing complexity and cost while maintaining high emitter quality
Solution Approach 2:
The patent replaces expensive conventional vacuum deposition and ion implantation equipment with a relatively simpler laser writing system. This substitution reduces capital equipment costs and operational expenses while achieving comparable or superior emitter region quality through direct laser writing
3Productivity
If simplified deposition processes are used, then manufacturing efficiency and cost effectiveness are improved, but manufacturing precision and passivation quality may deteriorate
Solution Approach 1:
The patent achieves high passivation quality through precise control of laser processing parameters. By optimizing laser power density, scanning speed, and pulse duration, the process creates controlled thermal gradients that promote proper crystalline structure formation and emitter passivation, maintaining high manufacturing precision while using a simplified single-step process
Solution Approach 2:
The laser writing system inherently provides precise control over the emitter formation process through optical focusing and digital control of beam parameters. This substitution of mechanical deposition with laser-based direct writing maintains manufacturing precision while simplifying the overall process
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 results in high-efficiency, low-cost solar cells with reduced manufacturing costs and improved passivation quality, enabling their inclusion in the premium solar cell market while minimizing the risk of emitter push effects and dopant diffusion.
Implementation Method 1
followed by laser doping to drive phosphorous dopants into the emitter regions
Implementation Method 2
forming multiple silicon layers and a phosphosilicate glass layer on a template substrate within an epitaxial deposition chamber
Data Source
AI summary
Methods of fabricating solar cells using simplified deposition processes, and the resulting solar cells, are described. In an example, a method of fabricating a solar cell involves loading a template substrate into a deposition chamber and, without removing the template substrate from the deposition chamber, performing a deposition method. The deposition method involves forming a first silicon layer on the template substrate, the first silicon layer of a first conductivity type. The deposition method also involves forming a second silicon layer on the first silicon layer, the second silicon layer of the first conductivity type. The deposition method also involves forming a third silicon layer above the second silicon layer, the third silicon layer of a second conductivity type. The deposition method also involves forming a solid state doping layer on the third silicon layer, the solid state doping layer of the first conductivity type.