Temporal and spatial atomic layer deposition of Al-doped zinc oxide as a passivating conductive contact for silicon solar cells

Macco, Bart; Poll, Mike L. van de; Loo, Bas W. H. van de; Broekema, Tim M.P.; Basuvalingam, Saravana Balaji; Helvoirt, Cristian A. A. van; Berghuis, Wilhelmus J. H.; Theeuwes, Roel J.; Phung, Nga; Kessels, W.M.M.

doi:10.1016/j.solmat.2022.111869

Cited by 6 publications

(4 citation statements)

References 32 publications

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“…35 and 21% smaller than that of H 2 O-ALD, respectively, regardless of high vapor pressure of the alcohol oxidants. In previous studies, nucleation delay was observed for ZnO ALD using DEZ and H 2 O on clean H-terminated Si substrates after HF treatment. , However, no nucleation delay was observed in current work for all ALD processes. Thus, it is speculated that some native oxide may have been generated on the Si substrate after HF cleaning due to delay of experimental procedure.…”

Section: Resultscontrasting

confidence: 58%

Rational Molecular Design for Non-aqueous Atomic Layer Deposition of Zinc Oxide

et al. 2023

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Zinc oxide (ZnO) is a transparent wide band gap semiconductor material with various possible applications in form of thin films. Most previous studies on atomic layer deposition (ALD) of ZnO thin films utilized a few well-known processes with diethylzinc (DEZ) and counter-reactants such as H2O and O3. However, O3 and H2O reactants have relatively strong reactivity, so that they are not suitable for substrates sensitive to oxidation. Therefore, development of milder non-aqueous alternative ALD process for ZnO is highly desired. In this study, we introduce ALD of ZnO using alcohols with theoretically optimized molecular structure. To discover suitable alcohol reactants for ZnO ALD, reaction pathways and reactivity between various types of alcohol reactants with surface-ethyl groups were evaluated through density functional theory calculations. It was found that unsaturated allylic alcohols would have the lowest activation energy for ZnO ALD via an allylic rearrangement mechanism. Experimental, novel ALD processes for ZnO using DEZ with alcohol as oxygen sources are set up. Ethanol as a typical simple alcohol is compared to 2-methyl-3-buten-2-ol (MBO) as an alcohol with optimal molecular structure setup. ALD ZnO films using MBO showed processes and material properties comparable to those of H2O-ALD ZnO. ZnO thin films as transparent conducting oxide could be obtained, and device performances of thin-film transistors based on alcohol-ALD processes are evaluated.

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Section: Resultscontrasting

confidence: 58%

Rational Molecular Design for Non-aqueous Atomic Layer Deposition of Zinc Oxide

et al. 2023

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“…In Fig. 2 (e), the doped SiN layer is deposited using PECVD or ALD [29][30][31][32] with uniform distribution. For this process, diborane or phosphine can be introduced into the chamber as dopants for N and P-doped SiN layer.…”

Section: Proposed Structurementioning

confidence: 99%

Improvement of Retention Characteristics Using Doped SiN Layer Between WL Spaces in 3D NAND Flash

Kyung,

Suh,

Jung

et al. 2024

IEEE Access

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We propose a novel structure of a charge trapping layer, that is doped between Word Line(WL) spaces in 3D NAND flash memory. To estimate the retention characteristics, the ∆Vth of each structure by doping type is compared to a reference structure during retention operation. In this study, lateral charge spreading, rather than vertical loss, is mainly studied as an indicator to determine how long stored data can survive on the selected cell. When the SiN layer is doped with p-type, the electrostatic potential decreases and SRH recombination increases in the doping region. As a result, the p-type doping structure has better retention characteristics than others. In addition, for an optimized structure between retention characteristics and cell current, the doping region of the SiN layer is split and analyzed by the thickness of the doping region. Since the p-type doping region is thicker, lateral spreading is effectively blocked although the cell current decreased slightly.

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“…A second likely mechanism is the presence of a separate energy barrier for hydrogenation of the SiO 2 /c-Si(n) interface aside from the temperature required for hydrogen to diffuse through the poly-Si. In related work from our group, the passivation by c-Si/SiO 2 /ZnO:Al/Al 2 O 3 stacks has been studied, which closely resemble the c-Si/SiO 2 /poly-Si(n)/ZnO:Al/Al 2 O 3 stacks of [21], [22], and [23]. While in that case, the hydrogen present in the ZnO:Al does not have to diffuse through the poly-Si, very similar optimal annealing temperatures for passivation were found in the range of 450-500 °C.…”

Section: Role Of Hydrogen Retainment In the Layersmentioning

confidence: 99%

“…1) [20]. Furthermore, it has been shown that ALD Al-doped ZnO on thin SiO 2 with Al 2 O 3 capping is an excellent passivating contact for n + diffused doped Si surfaces [21], [22], [23]. In this case, hydrogenation of poly-Si enables an implied open-circuit voltage (iV OC ) of more than 735 mV [13].…”

Section: Introductionmentioning

confidence: 99%

Effective Hydrogenation of Poly-Si Passivating Contacts by Atomic-Layer-Deposited Nickel Oxide

Phung

Helvoirt

Beyer³

et al. 2022

IEEE J. Photovoltaics

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In recent years, passivating contacts based on SiO 2 /poly-Si have proven to be an enabling technology for Si solar cells. Effective hydrogenation of the interfacial SiO 2 is vital for realizing efficient contacts. Hydrogen-rich dielectrics, such as SiN x and Al 2 O 3 , are commonly employed for hydrogenation, whereas also recently, n-type conductive oxides, such as In 2 O 3 :Sn and ZnO, have been demonstrated to yield excellent hydrogenation. This study presents the use of a p-type metal oxide, specifically NiO, as a suitable hydrogenation source. The p-type character of NiO makes it an interesting candidate for hydrogenation because of its potential use in selective contacting structures. Herein, we show that NiO, synthesized by atomic layer deposition (ALD), can be used to hydrogenate poly-Si/SiO 2 contacts effectively. Furthermore, we benchmark its hydrogenation performance to the established ALD ZnO/Al 2 O 3 stack and provide insights into the hydrogenation process. On planar surfaces, NiO yields almost as excellent results as ZnO/Al 2 O 3 stacks, whereas it lags behind on more challenging textured surfaces. Interestingly, even though elastic recoil detection analysis reveals that ALD NiO is rich in hydrogen, secondary ion mass spectrometry measurements show that, when NiO is compared to the ZnO/Al 2 O 3 stack, less hydrogen is present at the Si/SiO 2 interface after annealing. This is explained from effusion measurements, which show substantial effusion of hydrogen from NiO around 300 °C. Hence, Al 2 O 3 capping is further employed to prevent hydrogen loss and on textured wafers, the NiO/Al 2 O 3 stacks on poly-Si achieve an implied open-circuit voltage of 728 mV, confirming the excellent hydrogenation from ALD metal oxides.

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Temporal and spatial atomic layer deposition of Al-doped zinc oxide as a passivating conductive contact for silicon solar cells

Cited by 6 publications

References 32 publications

Rational Molecular Design for Non-aqueous Atomic Layer Deposition of Zinc Oxide

Rational Molecular Design for Non-aqueous Atomic Layer Deposition of Zinc Oxide

Improvement of Retention Characteristics Using Doped SiN Layer Between WL Spaces in 3D NAND Flash

Effective Hydrogenation of Poly-Si Passivating Contacts by Atomic-Layer-Deposited Nickel Oxide

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