Low‐Temperature Saw Damage Gettering to Improve Minority Carrier Lifetime in Multicrystalline Silicon

Al‐Amin, Mohammad; Grant, Nicholas E.; Murphy, John D.

doi:10.1002/pssr.201700268

Cited by 5 publications

(3 citation statements)

References 19 publications

(31 reference statements)

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“…[21,96,104] Their methodology has unambiguously shown lifetime improvements to arise from gettering and not due to bulk passivation. Recently, I-E passivation has also been used to demonstrate the effectiveness of saw damage at the wafer surfaces to getter impurities at 700 C. [105] In summary, whilst the side-effects of dielectric passivation are usually beneficial to PV device performance, it is usually better to use temporary passivation to study defect behavior in the material as the variables of interest are easier to isolate.…”

Section: Minimising Hydrogenation and External Gettering Effectsmentioning

confidence: 99%

Temporary Surface Passivation for Characterisation of Bulk Defects in Silicon: A Review

Grant

Murphy

2017

Physica Rapid Research Ltrs

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Accurate measurements of the bulk minority carrier lifetime in high-quality silicon materials is challenging due to the influence of surface recombination. Conventional surface passivation processes such as thermal oxidation or dielectric deposition often modify the bulk lifetime significantly before measurement. Temporary surface passivation processes at room or very low temperatures enable a more accurate measurement of the true bulk lifetime, as they limit thermal reconfiguration of bulk defects and minimize bulk hydrogenation. In this article we review the state-of-the-art for temporary passivation schemes, including liquid immersion passivation based upon acids, halogen-alcohols and benzyl-alcohols, and thin film passivation usually based on organic substances. We highlight how exceptional surface passivation (surface recombination velocity below 1 cm s À1 ) can be achieved by some types of temporary passivation. From an extensive review of available data in the literature, we find p-type silicon can be best passivated by hydrofluoric acid containing solutions, with superacid-based thin films showing a slight superiority in the n-type case. We review the practical considerations associated with temporary passivation, including sample cleaning, passivation activation, and stability. We highlight examples of how temporary passivation can assist in the development of improved silicon materials for photovoltaic applications, and provide an outlook for the future of the field.

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Section: Minimising Hydrogenation and External Gettering Effectsmentioning

confidence: 99%

Temporary Surface Passivation for Characterisation of Bulk Defects in Silicon: A Review

Grant

Murphy

2017

Physica Rapid Research Ltrs

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“…There are two types of SDG methods: high-temperature [25,26] and low-temperature methods. [27] The low-temperature method requires a long processing time (≈100 h) [27] ; thus, it is unsuitable for the mass production of Si wafer-based solar cells. The SDG method uses the surface saw damage caused by the wire-sawing operation as the gettering sites.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, crystallization enabled an effective texture formation during the essential etching process for SDG. [25][26][27]…”

Section: Introductionmentioning

confidence: 99%

A Grain Orientation‐Independent Single‐Step Saw Damage Gettering/Wet texturing Process for Efficient Silicon Solar Cells

Jung

Min

Post

et al. 2023

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Improving electrical and optical properties is important in manufacturing high‐efficiency solar cells. Previous studies focused on individual gettering and texturing methods to improve solar cell material quality and reduce reflection loss, respectively. This study presents a novel method called saw damage gettering with texturing that effectively combines both methods for multicrystalline silicon (mc‐Si) wafers manufactured using the diamond wire sawing (DWS) method. Although mc‐Si is not the Si material currently used in photovoltaic products, the applicability of this method using the mc‐Si wafers as it contains all grain orientations is demonstrated. It utilizes saw damage sites on the wafer surfaces for gettering metal impurities during annealing. Additionally, it can crystallize amorphous silicon on wafer surfaces generated during the sawing process to allow conventional acid‐based wet texturing. This texturing method and annealing for 10 min allow for the removal of metal impurities and effectively forms a textured DWS Si wafer. The results show that the open‐circuit voltage (ΔVoc = +29 mV), short‐circuit current density (ΔJsc = +2.5 mA cm−2), and efficiency (Δη = +2.1%) improved in the p‐type passivated emitter and rear cells (p‐PERC) manufactured using this novel method, as compared to those in the reference solar cells.

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Metal Impurities and Gettering in Crystalline Silicon

Yakimov¹

2019

Handbook of Photovoltaic Silicon

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Low‐Temperature Saw Damage Gettering to Improve Minority Carrier Lifetime in Multicrystalline Silicon

Cited by 5 publications

References 19 publications

Temporary Surface Passivation for Characterisation of Bulk Defects in Silicon: A Review

Temporary Surface Passivation for Characterisation of Bulk Defects in Silicon: A Review

A Grain Orientation‐Independent Single‐Step Saw Damage Gettering/Wet texturing Process for Efficient Silicon Solar Cells

Metal Impurities and Gettering in Crystalline Silicon

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