Correlative analysis of embedded silicon interface passivation by Kelvin probe force microscopy and corona oxide characterization of semiconductor

Aubriet, Valentin; Courouble, Kristell; Gros-Jean, M.; Borowik, Łukasz

doi:10.1063/5.0052885

Cited by 10 publications

(18 citation statements)

References 37 publications

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“…HfO 2 deposited under our conditions has the same charge polarity as Al 2 O 3 , that is negatively charged. This agrees well with findings of Aubreit et al [34] The magnitude of the surface photovoltage can be indicative of the quantity of charge present results can be highly variable and dependent on both material properties and surface defects. [34,49] Thus, we applied positive corona charging to characterize the negative fixed charge present in Al 2 O 3 and HfO 2 more reliably.…”

Section: Calculated Thickness [Nm]supporting

confidence: 93%

“…This agrees well with findings of Aubreit et al [34] The magnitude of the surface photovoltage can be indicative of the quantity of charge present results can be highly variable and dependent on both material properties and surface defects. [34,49] Thus, we applied positive corona charging to characterize the negative fixed charge present in Al 2 O 3 and HfO 2 more reliably. Applying extrinsic positive charge (Q corona ) via corona charging counteracts the built-in negative charges, thereby neutralizing the contribution of field effects, and c) 0.9 nm HfO 2 .…”

Section: Calculated Thickness [Nm]supporting

confidence: 93%

“…[14,19] Differing charge polarities may be a consequence of the deposition conditions. Many reports on ALD-grown HfO 2 involve thermal ALD, with positive fixed charges being observed using tetrakis(methylethylamide) hafnium and trimethylhafnium precursors, [13,31,33] and negative charges being reported with tetrakis(dimethylamido)hafnium, [14] trimethylhafnium, [19] and hafnium tetrachloride [34] precursors. HfO 2 deposited under our conditions has the same charge polarity as Al 2 O 3 , that is negatively charged.…”

Section: Calculated Thickness [Nm]mentioning

confidence: 99%

“…[30] Several recent studies have identified HfO 2 as a potential passivating layer, [14,31,32] due to its high dielectric constant, thermal stability, and electrical properties. [19] HfO 2 passivation studies have achieved a surface recombination velocity (SRV) <10 cm s −1 (compared to <2 cm s −1 for SiO 2 [26] and <1 cm s −1 for Al 2 O 3 [18,28] ) with film thicknesses of 10-20 nm, [13,14,19,[31][32][33][34] with the lowest SRV (1.2 cm s −1 ) reported by Gougam et al [33] There are conflicting reports on the polarity of the fixed charge in HfO 2 films, [13,14,19,[31][32][33][34] with charge magnitude commonly reported to be in the 10 11 -10 12 q cm −2 range. [14,19,34] This paper demonstrates that ultra-thin (<3 nm) oxides (SiO 2 , Al 2 O 3 , and HfO 2 ) grown by atomic-layer deposition (ALD) can act as highly effective passivation layers.…”

Section: Introductionmentioning

confidence: 99%

“…[19] HfO 2 passivation studies have achieved a surface recombination velocity (SRV) <10 cm s −1 (compared to <2 cm s −1 for SiO 2 [26] and <1 cm s −1 for Al 2 O 3 [18,28] ) with film thicknesses of 10-20 nm, [13,14,19,[31][32][33][34] with the lowest SRV (1.2 cm s −1 ) reported by Gougam et al [33] There are conflicting reports on the polarity of the fixed charge in HfO 2 films, [13,14,19,[31][32][33][34] with charge magnitude commonly reported to be in the 10 11 -10 12 q cm −2 range. [14,19,34] This paper demonstrates that ultra-thin (<3 nm) oxides (SiO 2 , Al 2 O 3 , and HfO 2 ) grown by atomic-layer deposition (ALD) can act as highly effective passivation layers. We conduct a detailed investigation to determine the optimal processing conditions to maximize the passivation level, the charge polarity, and magnitude in each case.…”

Section: Introductionmentioning

confidence: 99%

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Electronic Characteristics of Ultra‐Thin Passivation Layers for Silicon Photovoltaics

Pain

Khorani

Niewelt

et al. 2022

Adv Materials Inter

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on PERC technologies and get even closer to the theoretical single-junction efficiency limit, electrical losses in the contacted regions must be reduced. [3][4][5] Passivating contacts can help alleviate such losses by simultaneously suppressing the current of non-collected carriers to the contact, and by reducing recombination sites at the interface. Introducing a passivating interlayer between the metal/silicon interface provides a route to reducing the recombination current density, J 0 , [6,7] thereby increasing device voltage. [3] Passivating contacts have achieved some success to date, with the strongest candidates being polysilicon on top of thin silicon oxide layers (e.g., tunnel oxide passivating contacts (TOPCon) or poly silicon on oxide (POLO)) and amorphous silicon (a-Si) heterojunctions. [3,7,8] TOPCon is an efficient electron-selective contact but has a high thermal budget with temperatures around 900 °C needed to reduce the contact resistivity to acceptable levels. [9] An efficient hole-selective layer that can match or exceed the performance of the current electron-selective materials would be of considerable interest. The use of SiO 2 -based hole-selective contacts has so far failed to reach equivalent levels. [10,11] The most promising hole-selective contacting materials are p-type a-Si and siliconrich SiC, but conventional high-temperature Ag screen printing methods are not necessarily compatible with such contacts. [10] Surface passivating thin films are crucial for limiting the electrical losses during charge carrier collection in silicon photovoltaic devices. Certain dielectric coatings of more than 10 nm provide excellent surface passivation, and ultra-thin (<2 nm) dielectric layers can serve as interlayers in passivating contacts. Here, ultra-thin passivating films of SiO 2 , Al 2 O 3 , and HfO 2 are created via plasma-enhanced atomic layer deposition and annealing. It is found that thin negatively charged HfO 2 layers exhibit excellent passivation properties-exceeding those of SiO 2 and Al 2 O 3 -with 0.9 nm HfO 2 annealed at 450 °C providing a surface recombination velocity of 18.6 cm s −1 . The passivation quality is dependent on annealing temperature and layer thickness, and optimum passivation is achieved with HfO 2 layers annealed at 450 °C measured to be 2.2-3.3 nm thick which give surface recombination velocities ≤2.5 cm s −1 and J 0 values of ≈14 fA cm −2 . The superior passivation quality of HfO 2 nanolayers makes them a promising candidate for future passivating contacts in high-efficiency silicon solar cells.

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Section: Calculated Thickness [Nm]supporting

confidence: 93%

Section: Calculated Thickness [Nm]supporting

confidence: 93%

Section: Calculated Thickness [Nm]mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Electronic Characteristics of Ultra‐Thin Passivation Layers for Silicon Photovoltaics

Pain

Khorani

Niewelt

et al. 2022

Adv Materials Inter

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Correlative Atomic Coordination and Interfacial Charge Polarity in Al₂O₃/GaN and Al₂O₃/Si Heterostructures

Wang

2022

Physica Rapid Research Ltrs

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Al2O3 is used to form Al2O3/GaN and Al2O3/Si heterostructures for many electronic and optoelectronic devices. Yet the origins of the positive interfacial charges in the Al2O3/GaN heterostructure and negative interfacial charges in the Al2O3/Si heterostructure are often elusive. Herein, in‐depth studies of the Al2O3/GaN and Al2O3/Si heterostructures are conducted, especially on how the atomic coordination structure affects the interfacial charges. It is discovered that the octahedral [AlO6]9− coordination surpassed tetrahedral [AlO4]5− coordination at the Al2O3/GaN interface, whereas tetrahedral [AlO4]5− coordination dominated at the Al2O3/Si interface. Therefore, the interfacial charge polarity is correlated with the nonstoichiometry atomic coordination of Al2O3 at the two interfaces. This study reveals the atomic origin of charge polarity at high‐k/semiconductor interfaces and could facilitate the development of high‐performance optoelectronic and electronic devices through engineering the atomic coordination structure of the high‐k materials.

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Atomic Layer Deposition of Hafnium Oxide Passivating Layers on Silicon: Impact of Precursor Selection

Pain,

Yadav,

Walker

et al. 2024

Physica Rapid Research Ltrs

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Hafnium oxide (HfOx) films grown by atomic layer deposition (ALD) have recently been demonstrated to provide high‐quality silicon surface passivation. Reports have suggested that changing the composition of the hafnium‐containing precursor can enable films of both charge polarities to be produced. Herein, the passivation quality of hafnium oxide grown with metal amide precursors and a tetrakis(ethylmethylamido)hafnium (TEMAHf) precursor is examined, considering film charge polarity, chemical‐ and field‐based passivation effects, and film crystallinity. Throughout, the properties of TEMAHf‐HfOx are benchmarked against that of hafnium oxide grown with a tetrakis(dimethylamido)hafnium precursor. It is found that precursor choice has no influence on the fixed negative charge polarity (of order −1012 q cm−2) of HfOx films grown via plasma‐enhanced ALD. TEMAHf‐HfOx passivation is influenced by post‐deposition annealing temperature and can passivate with a surface recombination velocity ≤3 cm s−1 on n‐type silicon, compared to surface recombination velocities ≤11 cm s−1 for TDMAHf‐HfOx of a similar thickness.

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Correlative analysis of embedded silicon interface passivation by Kelvin probe force microscopy and corona oxide characterization of semiconductor

Cited by 10 publications

References 37 publications

Electronic Characteristics of Ultra‐Thin Passivation Layers for Silicon Photovoltaics

Electronic Characteristics of Ultra‐Thin Passivation Layers for Silicon Photovoltaics

Correlative Atomic Coordination and Interfacial Charge Polarity in Al₂O₃/GaN and Al₂O₃/Si Heterostructures

Atomic Layer Deposition of Hafnium Oxide Passivating Layers on Silicon: Impact of Precursor Selection

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Correlative analysis of embedded silicon interface passivation by Kelvin probe force microscopy and corona oxide characterization of semiconductor

Cited by 10 publications

References 37 publications

Electronic Characteristics of Ultra‐Thin Passivation Layers for Silicon Photovoltaics

Electronic Characteristics of Ultra‐Thin Passivation Layers for Silicon Photovoltaics

Correlative Atomic Coordination and Interfacial Charge Polarity in Al2O3/GaN and Al2O3/Si Heterostructures

Atomic Layer Deposition of Hafnium Oxide Passivating Layers on Silicon: Impact of Precursor Selection

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Correlative Atomic Coordination and Interfacial Charge Polarity in Al₂O₃/GaN and Al₂O₃/Si Heterostructures