Nondestructive Contact Resistivity Measurements on Solar Cells Using the Circular Transmission Line Method

Gregory, Geoffrey; Li, Mengjie; Gabor, Andrew M.; Anselmo, Andrew; Yang, Zhihao; Ali, Haider; Iqbal, Nafis; Davis, Kristopher O.

doi:10.1109/jphotov.2019.2945173

Cited by 10 publications

(3 citation statements)

References 12 publications

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“…[50] Contact and junction resistivities of the poly-Si contact were measured using the transmission line method (TLM) [51] using a BrightSpot ContactSpot tool. [52][53][54] For the metal contact formation on the poly-Si layer, TLM pads with 5 mm length and 2.5 mm width were deposited using an e-beam evaporated 30 nm titanium (Ti) layer capped by around 300 nm aluminum (Al) layer. TLM pads were deposited with varying gaps in between them.…”

Section: Methodsmentioning

confidence: 99%

Process–Structure–Properties Relationships of Passivating, Electron‐Selective Contacts Formed by Atmospheric Pressure Chemical Vapor Deposition of Phosphorus‐Doped Polysilicon

Mousumi

Gregory

Ganesan

et al. 2022

Physica Rapid Research Ltrs

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Herein, we investigate the process–structure–properties relationships of in situ phosphorus (P)‐doped polycrystalline silicon (poly‐Si) films by atmospheric pressure chemical vapor deposition (APCVD) for fabricating poly‐Si passivating, electron selective contacts. This high‐throughput in‐line APCVD technique enables to achieve a low‐cost, simple manufacturing process for crystalline silicon (c‐Si) solar cells featuring poly‐Si passivating contact by excluding the need for vacuum/plasma environment, and additional post‐deposition doping steps. A thin layer of this P‐doped poly‐Si is deposited on an ultrathin (1.5 nm) silicon oxide (SiO x ) coated c‐Si substrate to fabricate the passivating contact. This is followed by various post‐deposition treatments, including a high‐temperature annealing step and hydrogenation process. The poly‐Si films are characterized to achieve a better understanding of the impacts of deposition process conditions and post‐deposition treatments on the microstructure, electrical conductivity, passivation quality, and carrier selectivity of the contacts which assists to identify the optimal process conditions. In this work, the optimized annealing process with post‐hydrogenation yields passivating contact with a saturation current density (J 0) of 3 fA cm−2 and an implied open‐circuit voltage (iV OC) of 712 mV on planar c‐Si wafer. Junction resistivity values ranging from 50 to 260 mΩ cm2 are realized for the poly‐Si contacts processed in the optimal annealing condition.

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Section: Methodsmentioning

confidence: 99%

Process–Structure–Properties Relationships of Passivating, Electron‐Selective Contacts Formed by Atmospheric Pressure Chemical Vapor Deposition of Phosphorus‐Doped Polysilicon

Mousumi

Gregory

Ganesan

et al. 2022

Physica Rapid Research Ltrs

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“…The metal/poly-Si ρ c was measured using transmission line measurements (TLMs) [69] with a BrightSpot ContactSpot tool [70][71][72]. For the metal contact formation, approximately 200 nm thick Al TLM pads were deposited using e-beam evaporation on one side of the symmetrical sample (figure 5).…”

Section: Experimental Methodsmentioning

confidence: 99%

Phosphorus-doped polysilicon passivating contacts deposited by atmospheric pressure chemical vapor deposition

Mousumi¹,

Ali²,

Gregory³

et al. 2021

J. Phys. D: Appl. Phys.

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In this work, we present a high quality tunnel oxide passivating, electron-selective contact that is formed using an in-situ phosphorus-doped polycrystalline silicon (poly-Si) layer deposited using an in-line atmospheric pressure chemical vapor deposition (APCVD) process. In-line APCVD is a single-sided deposition process that does not require vacuum systems and is well suited for high volume manufacturing. To fabricate this tunnel oxide passivating contact (TOPCon), we deposit an amorphous silicon (a-Si) layer on silicon oxide (SiO) passivated n-type crystalline silicon (c-Si) followed by an annealing step at around 910 ∘C, which provides solid phase crystallization. The contact shows an excellent surface passivation quality with an effective minority carrier lifetime of ≈4.2 ms and an implied open circuit voltage (iV ) of ≈717 mV after annealing without any additional hydrogenation process. Saturation current density (J ) of ≈18 fA cm−2 is recorded for this contact. Contact resistivity () of ≈50 mΩ·cm−2 and junction resistivity of ≈0.24 Ω·cm−2 are realized with e-beam evaporated aluminium (Al) metal contact.

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“…The resistivity is understood to be the quantity that characterises the metal–semiconductor junction, considering the area above and below the junction. The value of contact resistance, which depends on the type of paste used, the substrate resistance, and the temperature of the metallisation process, can be determined experimentally—for example, by using the TLM (transmission line model) method [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] or the PD (potential differences) method [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. In the case of the TLM method, the measurement consists of forcing an electric current signal between the selected pair of adjacent front conductive lines on the tested sample through the supply soda and the spontaneous generation of a potential difference in them through the measuring probes ( Figure 1 a).…”

Section: Methods Applied To Measuring Selected Parameters Of the Electrical Properties Of Photovoltaic Cellsmentioning

confidence: 99%

Comparison of the Values of Solar Cell Contact Resistivity Measured with the Transmission Line Method (TLM) and the Potential Difference (PD)

Musztyfaga-Staszuk

2021

Materials

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This work presents a comparison of values of the contact resistivity of silicon solar cells obtained using the following methods: the transmission line model method (TLM) and the potential difference method (PD). Investigations were performed with two independent scientific units. The samples were manufactured with silver front electrodes. The co-firing process was performed in an infrared belt furnace in a temperature range of 840 to 960 °C. The electrical properties of a batch of solar cells fabricated in two cycles were investigated. This work focuses on the different metallisation temperatures of co-firing solar cells and measurements were carried out using the methods mentioned. In the TLM and PD methods, the same calculation formulae were used. Moreover, solar cell parameters measured with these methods had the same, similar, or sometimes different but strongly correlated values. Based on an analysis of the selected databases, this article diagnoses the recent and current state of knowledge regarding the employment of the TLM and PD methods and the available hardware base. These methods are of interest to various research centres, groups of specialists dealing with the optimisation of the electrical properties of silicon photovoltaic cells, and designers of measuring instruments.

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Nondestructive Contact Resistivity Measurements on Solar Cells Using the Circular Transmission Line Method

Cited by 10 publications

References 12 publications

Process–Structure–Properties Relationships of Passivating, Electron‐Selective Contacts Formed by Atmospheric Pressure Chemical Vapor Deposition of Phosphorus‐Doped Polysilicon

Process–Structure–Properties Relationships of Passivating, Electron‐Selective Contacts Formed by Atmospheric Pressure Chemical Vapor Deposition of Phosphorus‐Doped Polysilicon

Phosphorus-doped polysilicon passivating contacts deposited by atmospheric pressure chemical vapor deposition

Comparison of the Values of Solar Cell Contact Resistivity Measured with the Transmission Line Method (TLM) and the Potential Difference (PD)

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