N-Type Bifacial Solar Cell Al2O3 Passivation at Low RF Frequency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for preparing N-type double-sided solar cells, particularly the use of thermal atomic layer deposition for aluminum oxide passivation, result in low open-circuit voltage and conversion efficiency due to inappropriate selection of radio-frequency power frequency in plasma-enhanced atomic layer deposition.
Innovation Solution
The method involves forming a front side aluminum oxide passivation layer using plasma-enhanced atomic layer deposition with a radio-frequency power frequency within the range of 40 kHz to 400 kHz and a deposition temperature of 80° C. to 400° C., allowing for the ionization of oxygen into a plasma to react with aluminum source molecules and form a dense, high-purity aluminum oxide film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermal atomic layer deposition is used to prepare aluminum oxide passivation layer, then the process is simple and easy to manufacture, but the open-circuit voltage and conversion efficiency are low
Solution Approach 1:
The patent changes the deposition method from thermal atomic layer deposition to plasma-enhanced atomic layer deposition, and optimizes parameters including radio-frequency power frequency (40-400 kHz), deposition temperature (80-400°C), and introduces specific gaseous aluminum and oxygen sources. These parameter changes enable formation of denser, higher purity aluminum oxide films with better passivation performance, achieving open-circuit voltage above 715 mV and conversion efficiency above 24.5%
2Manufacturing precision
If plasma-enhanced atomic layer deposition is used with conventional radio-frequency power frequency, then film quality improves, but energy consumption increases and the process becomes complex
Solution Approach 1:
The patent identifies and optimizes the radio-frequency power frequency parameter to the specific range of 40-400 kHz, which enables effective plasma generation for aluminum oxide film formation while controlling energy consumption. This parameter optimization allows the process to achieve high film quality (density, purity, uniformity) without excessive energy input, making the plasma-enhanced process practical for manufacturing
3Manufacturing precision
If high radio-frequency power frequency is used in plasma-enhanced atomic layer deposition, then aluminum oxide film density improves, but deposition temperature increases excessively
Solution Approach 1:
The patent optimizes the radio-frequency power frequency to the range of 40-400 kHz, which provides sufficient plasma energy to form dense aluminum oxide films at moderate temperatures (80-400°C). This frequency optimization decouples the need for high temperature from film density achievement, allowing dense film formation through plasma activation rather than thermal energy alone
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 enhances the open-circuit voltage and conversion efficiency of N-type double-sided solar cells by improving the passivation performance and film quality at lower temperatures and frequencies, leading to better film uniformity and reduced energy consumption.
Implementation Method 1
a gaseous oxygen source is introduced, such that the oxygen source is ionized into a plasma and reacts with the aluminum source to obtain aluminum oxide
Implementation Method 2
the oxygen source is ionized into a plasma
Implementation Method 3
a gaseous aluminum source is firstly introduced into the plasma apparatus in a vacuum state, such that a layer of aluminum source molecules is adsorbed on a surface of the silicon wafer
Data Source
AI summary
An N-type double-sided solar cell preparation method comprises: sequentially forming a front aluminum oxide passivation layer and a front silicon nitride anti-reflection layer on a front face of an N-type silicon wafer. The front aluminum oxide passivation layer is prepared by using a plasma-enhanced atomic layer deposition method, and the deposition conditions thereof involve: any frequency in the frequency range of 40 kHz to 400 kHz is selected to be a radio-frequency power supply frequency, a gaseous aluminum source is first introduced into a plasma apparatus in a vacuum state, such that a layer of aluminum source molecules is adsorbed on the surface of the silicon wafer, and a gaseous oxygen source is then introduced, such that the oxygen source is ionized into plasma and reacts with the aluminum source to obtain aluminum oxide.