High-temperature stability of c-Si surface passivation by thick PECVD Al2O3 with and without hydrogenated capping layers

Saint‐Cast, Pierre; Kania, D.; Heller, R.; Kuehnhold, Saskia; Hofmann, M.; Rentsch, J.; Preu, R.

doi:10.1016/j.apsusc.2012.03.171

Cited by 43 publications

(22 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…64 Further, a correlation between void density and layer stress release in carbon films on Si was shown by Puchert et al 65 In this context, it might be interesting to connect these observations to other thickness dependent phenomena known from Al 2 O 3 layers like blistering. 16,66,67 Here, the density of temperature-induced bubbles within Al 2 O 3 layers was observed to increase dramatically with increasing Al 2 O 3 layer thickness. 16,66,67 Thus, the higher void density observed in this contribution for thick Al 2 O 3 layers might lead to a higher capture probability for hydrogen components.…”

Section: Interpretation and Discussionmentioning

confidence: 91%

“…16,66,67 Here, the density of temperature-induced bubbles within Al 2 O 3 layers was observed to increase dramatically with increasing Al 2 O 3 layer thickness. 16,66,67 Thus, the higher void density observed in this contribution for thick Al 2 O 3 layers might lead to a higher capture probability for hydrogen components. With increasing temperature, the gas pressure might increase within these voids until they are destroyed.…”

Section: Interpretation and Discussionmentioning

confidence: 91%

See 1 more Smart Citation

A study on Si/Al2O3 paramagnetic point defects

Kühnhold-Pospischil

Saint‐Cast

Hofmann

et al. 2016

Journal of Applied Physics

View full text Add to dashboard Cite

In this contribution, negative charges and electronic traps related to the Si=Al 2 O 3 interface were measured and related to paramagnetic point defects and molecular vibrations. To this end, contactless capacitance voltage measurements, X-band electron paramagnetic resonance (EPR), and infrared spectroscopy were carried out, and their results were compared. A change in the negative charge density and electron trap density at the Si=Al 2 O 3 interface was achieved by adding a thermally grown SiO 2 layer with varying thicknesses and conducting an additional temperature treatment. Using EPR, five paramagnetic moments were detected in Si=ðSiO 2 Þ=Al 2 O 3 samples with g values of g 1 ¼ 2:008160:0002; g 2 ¼ 2:005460:0002; g 3 ¼ 2:000360:0002; g 4 ¼ 2:002660:0002, and g 5 ¼ 2:002960:0002. Variation of the Al 2 O 3 layer thickness shows that paramagnetic species associated with g 1 , g 2 , and g 3 are located at the Si=Al 2 O 3 interface, and those with g 4 and g 5 are located within the bulk Al 2 O 3 . Furthermore, g 1 , g 2 , and g 3 were shown to originate from oxygen plasma exposure during Al 2 O 3 deposition. Comparing the g values and their location within the Si=Al 2 O 3 system, g 1 and g 3 can be attributed to P b0 centers, g 3 to Si dangling bonds (Si-dbs), and g 4 and g 5 to rotating methyl radicals. All paramagnetic moments observed in this contribution disappear after a 5-min temperature treatment at 450 C. The deposition of an additional thermal SiO 2 layer between the Si and the Al 2 O 3 decreases the negative fixed charge density and defect density by about one order of magnitude. In this contribution, these changes can be correlated with a decrease in amplitude of the Si-db signal. P b0 and the methyl radical signals were less affected by this additional SiO 2 layer. Based on these observations, microscopic models for the negative fixed charge density (Q tot ) and the interface trap density (D it ) and the connection between these values are proposed. Published by AIP Publishing. [http://dx

show abstract

Section: Interpretation and Discussionmentioning

confidence: 91%

Section: Interpretation and Discussionmentioning

confidence: 91%

A study on Si/Al2O3 paramagnetic point defects

Kühnhold-Pospischil

Saint‐Cast

Hofmann

et al. 2016

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The surface of wafer is initially exposed to H 2 O during thermal ALD, while, oxygen radicals during plasma ALD . Hydrogen atoms are obtained independently from the capping SiN x layer and diffuse into the SiO 2 /bulk Si interface, which reduces the density of the interfacial dangling bonds and inactive recombination traps efficiently. Figure D shows the cross‐sectional finger shapes of a screen‐printed front Ag finger, which is typical in manufacturing, a printing Al finger, and a DP Al finger.…”

Section: Resultsmentioning

confidence: 99%

“…The capping double‐layer SiN x :H antireflection coating (DARC) that is prepared by PECVD can improve the thermal stability and hydrogen atomic concentration significantly after annealing of the 10 nm Al 2 O 3 passivated layer . In PERC+ solar cells, it is important to optimize the thickness and reflective index of the SiN x :H capping layer to obtain a low reflectance of the rear.…”

Section: Resultsmentioning

confidence: 99%

Efficiency enhancement of bifacial PERC solar cells with laser‐doped selective emitter and double‐screen‐printed Al grid

Zhang

Zheng

et al. 2018

Progress in Photovoltaics

View full text Add to dashboard Cite

We report that the application of a laser‐doped selective emitter (SE) can improve the trade‐off between the recombination in the emitter and the Ag‐Si specific contact resistance and that a double‐screen‐printed rear aluminum grid can decrease the series resistance in the industrial bifacial passivated emitter and rear cell (PERC). Our results reveal that a front‐side efficiency of 21.9% can be achieved in the PERC (SE)+ solar cell by using low surface‐recombination Al2O3/SiNx films as passivation layers, low‐recombination emitter, and low resistive Ag‐Si contact with an optimized sheet resistance of the lightly doped area of SE with 125Ω/sq and sheet resistance of the highly doped area of SE with 70 Ω/sq. The highest front‐side efficiency of 22.0%, with open‐circuit voltage of 680 mV, short‐circuit current density of 40.1 mA/cm2, and fill factors of 80.8%, is obtained by using double‐screen‐printed rear Al grid process, which is 0.1% higher than the best PERC (SE)+ solar cell. The rear‐side double‐layer antireflection coating consists of 50 nm SiNx:H (n = 2.1) and 10 nm SiNx:H (n = 2.37), which enables a large bifacial gain with the output power density PMPP of 25.5 mW/cm2 in the PERC (SE)+ solar cell by using double‐screen‐printed rear Al grid process when rear‐side illumination intensity Erear = 0.25 suns.

show abstract

“…[1][2][3][4] As plasmas are composed by energetic and/or reactive species, the precursor molecule is effectively activated without the needing of thermal heating, an advantage as one concern large-scale productions.…”

Section: Introductionmentioning

confidence: 99%

Preparation of films from aluminum acetylacetonate by plasma sputtering

Nielsen

Silva

Cruz

et al. 2013

Surface & Interface Analysis

View full text Add to dashboard Cite

Aluminum acetylacetonate has been reported as a precursor for the deposition of alumina films using different approaches. In this work, alumina-containing films were prepared by plasma sputtering this compound, spread directly on the powered lowermost electrode of a reactor, while grounding the substrates mounted on the topmost electrode. Radiofrequency power (13.56 MHz) was used to excite the plasma from argon atmosphere at a working pressure of 11 Pa. The effect of the plasma excitation power on the properties of the resulting films was studied. Film thickness and hardness were measured by profilometry and nanoindentation, respectively. The molecular structure and chemical composition of the layers were analyzed by Fourier transform infrared spectroscopy and energy dispersive spectroscopy. Surface micrographs, obtained by scanning electron microscopy, allowed the determination of the sample morphology. Grazing incidence X-ray diffraction was employed to determine the structure of the films. Amorphous organic layers were deposited with thicknesses of up to 7 mm and hardness of around 1.0 GPa. The films were composed by aluminum, carbon, oxygen and hydrogen, their proportions being strongly dependent on the power used to excite the plasma. A uniform surface was obtained for low-power depositions, but particulates and cracks appeared in the high-power prepared materials. The presence of different proportions of aluminum oxide in the coatings is ascribed to the different activations promoted in the metalorganic molecule once in the plasma phase.

show abstract

High-temperature stability of c-Si surface passivation by thick PECVD Al2O3 with and without hydrogenated capping layers

Cited by 43 publications

References 12 publications

A study on Si/Al2O3 paramagnetic point defects

A study on Si/Al2O3 paramagnetic point defects

Efficiency enhancement of bifacial PERC solar cells with laser‐doped selective emitter and double‐screen‐printed Al grid

Preparation of films from aluminum acetylacetonate by plasma sputtering

Contact Info

Product

Resources

About