Trap-Assisted Dopant Compensation Prevents Shunting in poly-Si Passivating Interdigitated Back Contact Silicon Solar Cells

Conference · Thu Aug 26 04:00:00 EDT 2021

DOI:https://doi.org/10.1109/PVSC43889.2021.9518637· OSTI ID:1823574

Hartenstein, Matthew B; Stetson, Caleb; Nemeth, William; LaSalvia, Vincenzo; Harvey, Steve; Page, Matthew; Jiang, Chun-Sheng; Al-Jassim, Mowafak; Young, David L.; Stradins, Paul; Agarwal, Sumit

Interdigitated back contact (IBC) solar cells achieve the highest efficiencies of single-junction architectures, but complicated patterning of the rear fingers and spreading of dopants during processing inhibit their mainstream adoption due to concerns of shunting between the IBC fingers. One method of simplifying patterning at the rear is by using contact masks combined with plasma-enhanced chemical vapor deposition (PECVD) or ion implantation. However, the intrinsic isolation region becomes contaminated during high-temperature annealing by lateral diffusion of dopants and during masked PECVD by spreading of dopant radicals through region between the mask and the substrate. Despite this contamination, we show through scanning spreading resistance microscopy and Kelvin probe force microscopy that a ~20 µm wide compensating region exists with high enough resistivity to prevent shunting. We model this p-i-n poly-Si system using two simulation models: a simple resistor model considering only the capture of charge carriers by trap defects in poly-Si to reduce the conductivity, and a more refined 1-dimensional finite element model using Poisson’s equation, drift-diffusion equations, and recombination of carriers. Using this model, we show that high defect density significantly decreases the current across the region between the p- and n-type fingers, preventing shunting.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1823574
• Report Number(s): NREL/CP-5900-80186; MainId:42389; UUID:64a1d289-9f0d-4e3c-b9fa-79ca8e800e6f; MainAdminID:25676
• Country of Publication: United States
• Language: English

Related Subjects

IBC
PECVD
SOLAR ENERGY
atom probe
interdigitated back contact
passivating contact
plasma enhanced chemical vapor deposition
silicon solar cell
simulation