Solar Cell Laser Doping Surface Damage Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser-induced dopant diffusion in crystalline wafer type solar cells damages the semiconductor surface, leading to poor contact characteristics and reduced efficiency due to surface damage.
Innovation Solution
A method involving the formation of an amorphous silicon layer, doping with a dopant, laser diffusion, and subsequent etching with a mixture of hydrogen fluoride, nitric acid, and water or other etchants to remove surface damage, improving electrode contact characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser-induced dopant diffusion is used to increase dopant concentration, then doping efficiency is improved, but surface damage is caused
Solution Approach 1:
An amorphous silicon layer is formed on the light absorbing layer before laser-induced dopant diffusion. This preliminary layer acts as a protective buffer that absorbs the laser energy and prevents direct damage to the crystalline semiconductor surface while still allowing dopant diffusion to occur effectively.
Solution Approach 2:
The laser-induced surface damage is converted into a beneficial process by using it to create an amorphous silicon layer. This layer, which initially appears as damage, actually serves as a protective medium that enables effective dopant diffusion while preventing further damage to the underlying crystalline structure.
2Ease of manufacture
If surface damage is present, then manufacturing process is simpler, but electrode contact characteristic is poor
Solution Approach 1:
The damaged or amorphous silicon layer is selectively removed through etching processes after dopant diffusion is complete. This extraction eliminates the harmful surface damage while preserving the beneficial dopant concentration profile that was established during the diffusion process.
Solution Approach 2:
The amorphous silicon layer serves as an intermediary medium during the manufacturing process. It facilitates dopant diffusion and then is removed to reveal the improved contact surface, acting as a temporary mediator that enables the process but is not part of the final structure.
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
The etching process effectively removes surface damage, enhancing the contact characteristics of electrodes and improving solar cell efficiency by creating a smoother interface for electrode formation.
Implementation Method 1
doping the amorphous silicon layer with a dopant; forming a dopant layer by diffusing the dopant into the amorphous silicon layer with a laser
Implementation Method 2
etching the surface of the semiconductor layer by using an etchant; soaking the surface of the semiconductor layer in the etchant for 1 to 3 minutes
Data Source
AI summary
A method for manufacturing a solar cell is presented. The method includes: forming an amorphous silicon layer on a first surface of a light absorbing layer; doping the amorphous silicon layer with a dopant; forming a dopant layer by diffusing the dopant into the amorphous silicon layer with a laser; forming a semiconductor layer by removing the dopant that remains outside the dopant layer; etching the surface of the semiconductor layer by using an etchant; forming a first electrode on the semiconductor layer; and forming a second electrode on a second surface of the light absorbing layer.