1.
N Wehmeier; B Lim; A Merkle; A Tempez; S Legendre; H Wagner; A Nowack; T Dullweber; P P Altermatt
PECVD BSG diffusion sources for simplified high-efficiency n-PERT BJ and BJBC solar cells Artikel
In: IEEE Journal of Photovoltaics, Bd. 6, Nr. 1, S. 119-125, 2016.
@article{Wehmeier2016c,
title = {PECVD BSG diffusion sources for simplified high-efficiency n-PERT BJ and BJBC solar cells},
author = {N Wehmeier and B Lim and A Merkle and A Tempez and S Legendre and H Wagner and A Nowack and T Dullweber and P P Altermatt},
doi = {10.1109/JPHOTOV.2015.2493364},
year = {2016},
date = {2016-01-01},
journal = {IEEE Journal of Photovoltaics},
volume = {6},
number = {1},
pages = {119-125},
abstract = {We investigate boron silicate glasses (BSG) deposited by plasma-enhanced chemical vapor deposition (PECVD) as a boron diffusion source on n-type wafers for the simplified fabrication of crystalline Si solar cells by the codiffusion processes. By varying the SiH4/B2 H6 gas flow ratio and the layer thickness of the PECVD BSG layers, we obtain sheet resistivities in a wide range from 30 to 500 Ω/□ after thermal B drive-in. Emitter saturation current densities as low as J0e = 4 fA/cm2 (for Rsheet = 236 Ω/□) are demonstrated using PECVD BSG layers as diffusion sources. A boron concentration in the PECVD BSG of up to 6.4 × 1021 cm-3 is measured by plasma profiling time-of-flight mass spectrometry (PP-TOFMS). A process simulation model of the B diffusion from the PECVD BSG into the Si substrate reproduces the experimental B concentration profile in the Si, measured both by PP-TOFMS and electrochemical capacitance- voltage (ECV) measurements. We fabricate industrial-type passivated emitter and rear totally diffused back-junction (PERT BJ) solar cells, as well as back-junction back-contact cells on n-type wafers. Applying codiffusion from PECVD BSG layers and thus a lean process flow including only one high-temperature step, we demonstrate n-PERT BJ cells with conversion efficiencies of up to 19.85%.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We investigate boron silicate glasses (BSG) deposited by plasma-enhanced chemical vapor deposition (PECVD) as a boron diffusion source on n-type wafers for the simplified fabrication of crystalline Si solar cells by the codiffusion processes. By varying the SiH4/B2 H6 gas flow ratio and the layer thickness of the PECVD BSG layers, we obtain sheet resistivities in a wide range from 30 to 500 Ω/□ after thermal B drive-in. Emitter saturation current densities as low as J0e = 4 fA/cm2 (for Rsheet = 236 Ω/□) are demonstrated using PECVD BSG layers as diffusion sources. A boron concentration in the PECVD BSG of up to 6.4 × 1021 cm-3 is measured by plasma profiling time-of-flight mass spectrometry (PP-TOFMS). A process simulation model of the B diffusion from the PECVD BSG into the Si substrate reproduces the experimental B concentration profile in the Si, measured both by PP-TOFMS and electrochemical capacitance- voltage (ECV) measurements. We fabricate industrial-type passivated emitter and rear totally diffused back-junction (PERT BJ) solar cells, as well as back-junction back-contact cells on n-type wafers. Applying codiffusion from PECVD BSG layers and thus a lean process flow including only one high-temperature step, we demonstrate n-PERT BJ cells with conversion efficiencies of up to 19.85%.