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Title: Electrical Analysis of Pulsed Laser Annealed Poly-Si: Ga/SiOx Passivating Contacts

Conference ·
DOI:https://doi.org/10.1063/5.0141158· OSTI ID:1997376
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In this contribution, we examine Ga hyper-doped poly-Si/SiOx contacts realized by pulsed laser melting (PLM). Here, we use Ga as a novel p-type dopant and B as a conventional dopant to induce non-equilibrium doping using an excimer laser. We perform simulations to visualize the maximum melt depth profiles within the poly-Si, with a goal of distributing dopants close to the tunneling oxide, but at the same time preserving the passivation. Hall measurements show that sheet resistance for B is lower than Ga due to its higher solid solubility limit in Si. After comparing the Hall active dopant concentration with the chemical concentration obtained by SIMS measurement, we show nearly 100% activation B activation reaching 10^21 cm-3, while only ~20% activation for Ga. Nevertheless, we achieve active doping concentrations of Ga in poly-Si six times higher than its solid solubility limit in Si (~10^19 cm-3). We compare our Hall mobilities with values in the literature for c-Si and show that B mobilities in laser-treated poly-Si are close to that of the literature value for B, while Ga mobilities are lower, possibly due to additional scattering channels within grain boundaries and deformed lattice. We also compare our results on PLM samples with conventional furnace annealed samples, and we show much higher percent activation and mobilities. Previously, we showed a low contact resistivity of 35.5 +/- 2.4 m..omega..cm2. Here, we further confirm this result by scanning spreading resistance microscopy and Kelvin force nanoprobe microscopy. We demonstrate that our poly-Si: Ga/nCz contact exhibits large drift and diffusion currents under normal cell operating voltage, which widens the laser processing window for a good metal/poly-Si/c-Si contact.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
DOE Contract Number:
AC36-08GO28308
OSTI ID:
1997376
Report Number(s):
NREL/CP-5K00-87324; MainId:88099; UUID:96e5a759-b83d-4b7d-b380-7feb1684f8fa; MainAdminID:70332
Resource Relation:
Conference: Presented at the SiliconPV 2022, the 12th International Conference on Crystalline Silicon Photovoltaics, 28-30 March 2022, Konstanz, Germany
Country of Publication:
United States
Language:
English

References (9)

Design rules for high-efficiency both-sides-contacted silicon solar cells with balanced charge carrier transport and recombination losses journal April 2021
Gallium-Doped Poly-Si:Ga/SiO2 Passivated Emitters to n-Cz Wafers With iV oc >730 mV journal November 2017
Solid Solubilities of Impurity Elements in Germanium and Silicon* journal January 1960
Experimental test of morphological stability theory for a planar interface during rapid solidification journal July 1998
An Expanded Cox and Strack Method for Precise Extraction of Specific Contact Resistance of Transition Metal Oxide/ n- Silicon Heterojunction journal July 2019
Electrical activation and lattice location of B and Ga impurities implanted in Si
  • Romano, Lucia; Piro, Alberto M.; Napolitani, Enrico
  • Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 219-220 https://doi.org/10.1016/j.nimb.2004.01.151
journal June 2004
Polycrystalline silicon passivated tunneling contacts for high efficiency silicon solar cells journal March 2016
Modeling of carrier mobility against carrier concentration in arsenic-, phosphorus-, and boron-doped silicon journal July 1983
Effect of Strain on the Carrier Mobility in Heavily Dopedp-Type Si journal September 2006

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SOLAR ENERGY
high-efficiency solar cells
poly-Si
pulsed laser melting