Antimony-Doped Silicon Ingot for Uniform Wafer Resistivity
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Solution Overview
Problem
The challenge in the photovoltaic industry is achieving a uniform resistivity range in N-type silicon wafers to minimize series resistance and carrier recombination, which affects the efficiency of solar cells, while current methods lead to increased costs due to shorter ingot lengths.
Innovation Solution
Control the concentration of antimony in monocrystalline silicon ingots within specific ranges to achieve uniform resistivity, reducing carrier transport resistance and suppressing defects, thereby improving cell efficiency and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phosphorus-doped single crystals are used for N-type silicon ingots, then the silicon wafers can be produced, but the resistivity difference between head and tail becomes large, affecting cell efficiency
Solution Approach 1:
The patent changes the doping element from phosphorus to antimony, which has different segregation behavior during crystal growth. This parameter change in the doping material enables better resistivity uniformity along the ingot length while maintaining high cell efficiency, directly resolving the contradiction between resistivity uniformity and ingot length productivity
2Manufacturing precision
If the ingot length is reduced to achieve narrower resistivity range, then resistivity uniformity improves, but actual crystal pulling costs increase
Solution Approach 1:
By changing the doping element to antimony with optimal concentration control, the patent achieves narrow resistivity range without reducing ingot length. This resolves the contradiction by finding a different parameter (doping element type and concentration) that enables both high precision and cost-effectiveness
3Reliability
If antimony concentration is increased to suppress vacancy defects, then oxygen precipitation is reduced, but Auger recombination may increase
Solution Approach 1:
The patent optimizes the antimony concentration within a specific range (4E+14 to 2E+16 atom/cm³) to balance defect suppression and recombination effects. This parameter optimization resolves the contradiction by finding the optimal concentration point where vacancy defects are suppressed without excessive Auger recombination
Solution Approach 2:
The patent establishes feedback control through precise measurement and adjustment of antimony concentration during the doping process. This enables real-time optimization to maintain the balance between defect suppression and recombination control, resolving the contradiction through continuous parameter monitoring and adjustment
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 controlled antimony concentration in silicon wafers results in uniform resistivity, enhancing cell efficiency by reducing lateral transport resistance, improving minority carrier lifetime, and increasing the length of ingots produced, thus lowering production costs and heat loss.
Implementation Method 1
the ingot contains antimony element; and the antimony elements at a concentration of 4E+14 atom/cm3 to 2E+16 atom/cm3
Implementation Method 2
the resistivity of the silicon wafer or the bare silicon wafer becomes uniform. Using such wafers to fabricate cells can reduce the lateral transport resistance of carriers
Implementation Method 3
formation of vacancy defects in the silicon crystal may be further suppressed by further controlling the concentration range of the antimony element, so that, in an aspect, less oxygen precipitation is formed after oxygen enters the silicon crystal
Implementation Method 4
a relatively low resistivity may cause severe carrier Auger recombination, both of which lower the efficiency of the solar cell
Data Source
AI summary
The present disclosure relates to a monocrystalline silicon ingot, a silicon wafer, a solar cell, a solar cell string, and a solar module. In an example monocrystalline silicon ingot, a concentration of an antimony element is 0.04E+16 atom/cm3 to 2E+16 atom/cm3 in the monocrystalline silicon ingot.