Interdigitated Back-Contact Solar Cell Isolation via Phosphorus-Doped Grooves
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Solution Overview
Problem
Interdigitated back contact solar cells suffer from poor isolation performance between P-type and N-type interdigitated regions, leading to increased internal losses and reduced output power due to carrier drift without passing through external circuits.
Innovation Solution
A method involving sequential arrangement of a tunneling layer and N-type polysilicon layer on a P-type silicon substrate, etching an isolation groove, performing phosphorus doping on the groove's sidewall and bottom surface, and removing phosphorus-doped layers to enhance electrical isolation, followed by passivation and metallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isolation grooves are used to separate P-type and N-type interdigitated regions, then physical isolation is achieved, but electrical isolation performance deteriorates due to carrier drift across isolation regions
Solution Approach 1:
The patent applies local quality by creating a phosphorus-doped neutral layer specifically at the isolation groove region with different doping characteristics than the surrounding interdigitated regions. This localized doping creates a high-resistance barrier precisely where isolation is needed, while leaving the functional P-type and N-type regions unchanged. The neutral layer's unique electrical properties (high sheet resistance) are confined to the isolation groove, providing targeted electrical isolation without affecting the overall device performance.
Solution Approach 2:
The patent changes the electrical parameters of the isolation groove by introducing phosphorus doping that creates a neutral layer with significantly different conductivity characteristics. The phosphorus doping concentration and depth are controlled to achieve a neutral layer with high sheet resistance, transforming the isolation groove from a simple physical separator into an electrical barrier. This parameter change effectively blocks carrier drift while maintaining the structural simplicity of the isolation groove design.
2Reliability
If physical distance between P-type and N-type regions is increased through grooves or barriers, then isolation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the isolation function with the existing isolation groove structure by integrating phosphorus doping directly into the groove. Instead of adding separate isolation barriers or increasing groove dimensions, the solution combines the physical groove with a chemically-modified neutral layer. This merging approach achieves superior electrical isolation while maintaining the simple groove-based structure, avoiding the need for additional complex isolation components.
3Reliability
If phosphorus doping is performed on isolation groove sidewall and bottom surface, then electrical isolation is enhanced, but manufacturing process complexity increases
Solution Approach 1:
The patent employs self-service by utilizing the isolation groove structure itself as the doping template. The groove's geometric confinement automatically limits phosphorus diffusion to the desired neutral layer region, eliminating the need for complex masking or patterning steps. The doping process self-organizes around the groove structure, creating the neutral layer precisely where needed while simplifying the overall manufacturing 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
Enhances electrical isolation between interdigitated regions, reducing internal losses and improving photoelectric conversion efficiency by counter-doping with phosphorus atoms to increase sheet resistance and reduce carrier concentration.
Implementation Method 1
arranging a tunneling layer and an N-type polysilicon layer on a back surface of a P-type silicon substrate
Implementation Method 2
performing phosphorus doping on a sidewall and a bottom surface of the isolation groove
Implementation Method 3
performing phosphorus ion implantation on a surface of the base silicon wafer
Implementation Method 4
interdigitated back contact solar cell
Data Source
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AI summary
The present application relates to the field of photovoltaic manufacturing, and in particular to an interdigitated back-contact solar cell and a manufacturing method therefor. The manufacturing method for an interdigitated back-contact solar cell comprises: sequentially arranging a tunneling layer and an N-type polysilicon layer on a backlight face of P-type substrate silicon, so as to obtain a basic silicon wafer; performing etching on a preset partition region of a backlight face of the basic silicon wafer, so as to obtain a patterned isolation groove, wherein the isolation groove separates a P-type interdigitated region from an N-type interdigitated region; performing phosphorus doping on a side wall and the bottom face of the isolation groove; removing the N-type polysilicon layer and the tunneling layer which have been subjected to phosphorus doping and are located in the P-type interdigitated region, so as to obtain a photovoltaic precursor, and performing lamination passivation on a surface of the photovoltaic precursor, and performing metallization, so as to obtain an interdigitated back-contact solar cell. In the present disclosure, the isolation groove is doped with phosphorus atoms, such that the conductivity of the side wall and the bottom face of the isolation groove is greatly weakened, thereby improving the photoelectric conversion efficiency of the cell.