Susanne Fritz

Bio: Susanne Fritz is an academic researcher from University of Konstanz. The author has contributed to research in topics: Passivation & Boron. The author has an hindex of 6, co-authored 16 publications receiving 154 citations.

Formation of Ag/Al Screen-Printing Contacts on B Emitters

Abstract: In this study, the contact formation process of Al containing Ag screen-printing pastes to BBr3-based B emitters on Si is investigated. Therefore, a detailed scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy study of top-view and cross-sectional samples was conducted. The possible influence of a SiN ∞ :H antireflection coating was considered by comparing contacts with and without a SiN ∞ :H layer. To analyze the role of the glass frit in the paste, the contact formation of pastes without glass was examined. The results indicate that the Ag/Al contact spots grow below the Si surface/SiN ∞ :H layer. The glass frit is only indispensable for etching the antireflection layer-it is not needed for melting the metal in the screen-printing paste. The realized experiments lead to a phenomenological model for the contact formation process of Al containing screen-printing pastes to boron emitters.

Influence of hydrogen on interstitial iron concentration in multicrystalline silicon during annealing steps

Abstract: The influence of in-diffusing atomic H into an annealed multicrystalline silicon (mc-Si) wafer on the concentration of interstitial iron [Fei] was investigated. Neighboring wafers with similar initial [Fei] were annealed with and without in-diffusing H. In-diffusion was realized by exposing the samples to a microwave induced remote hydrogen plasma at 400 °C. [Fei] was detected based on lifetime measurements before and after dissociating the FeB complex. Surface passivation was achieved by a quinhydrone-methanol solution at room temperature to avoid further temperature steps or in-diffusion of H during surface passivation. From [Fei] measurements before and after the annealing steps with and without H, the influence of H alone on [Fei] could be accessed. The results were compared to previous experiments where the same SiNx:H layers were used as surface passivation for multiple [Fei] measurements of mc-Si samples before and after several anneals at 400 °C. It could be shown that a H plasma atmosphere has a strong additional effect on the reduction of [Fei] compared to temperature effects alone. A formation of H-Fei complexes associated with the passivation of the electrical activity of Fei could be shown to be improbable because no depassivation of Fei could be observed in subsequent annealing steps at 400 °C.

Contacting boron emitters on n-type silicon solar cells with aluminium-free silver screen-printing pastes

Abstract: In the production of n-type Si solar cells, B diffusion is commonly applied to form the p+ emitter. Up to now, Ag screen-printing pastes, generally used to contact P emitters, had been incapable of reliably contact B emitters. Therefore, a small amount of Al is generally added to Ag pastes to allow for reasonable contact resistances. The addition of Al, however, results in deep metal spikes growing into the Si surface that can penetrate the emitter. Losses in open-circuit voltage are attributed to these deep metal spikes. In this investigation we demonstrate, that state-of-the-art Al-free Ag screen-printing pastes are capable to contact BBr3-based B emitters covered with different dielectric layers and reach specific contact resistances <1 mΩ cm2. Bifacial n-type solar cells with Al-free Ag pastes on both sides show efficiencies of up to 18.3% and series resistances <0.5 Ω cm2. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

N-type bi-facial solar cells with boron emitters from doped PECVD layers

Abstract: This work is mainly focused on an alternative method for emitter formation by means of boron diffusion from a boron-doped plasma-enhanced chemical vapor deposition (PECVD) doping source. With this approach only one high temperature process is necessary for emitter and BSF/FSF formation (co-diffusion), without depletion of surface doping concentration. This enables time and cost-efficient fabrication of solar cells with high conversion efficiencies, as shown in this work, on large area (156.25 cm) bi-facial devices with conversion efficiencies up to 19.7% measured with white back sheet. Furthermore, the contact formation with screen-printing of silver/aluminum (Ag/Al) pastes and its emitter shunting behavior due to Ag/Al spikes, varying with the firing conditions in a belt furnace, are of major interest. Low contact resistance values below 4 mΩcm can be realized with screen-printed Ag/Al contacts on 55 –70 Ω/sq PECVD boron emitters. In addition, Ag/Al spikes with a depth of around 1 – 3 μm could be detected with SEM measurements.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Quinhydrone/Methanol Treatment for the Measurement of Carrier Lifetime in Silicon Substrates : Semiconductors

Abstract: Quinhydrone/methanol treatment for the measurement of carrier lifetime in crystalline silicon substrates has been investigated. To estimate the surface passivation effect, the lifetimes of the silicon substrates were measured using the microwave photoconductive decay method. The measured lifetime is dependent on quinhydrone concentration and passivation time. The 0.01 mol/dm3 quinhydrone/methanol treatment exhibited a good passivation effect, and a very low surface recombination velocity was obtained. The quinhydrone/methanol treatment can provide a reliable lifetime map of silicon wafers since a constant lifetime value without degradation can be obtained. Therefore, the quinhydrone/methanol treatment can be used for estimating the bulk lifetime of silicon substrates.