Structural Changes in Flash Lamp Annealed Amorphous Si Layers Probed by Slow Positron Implantation Spectroscopy

Anwand, W.; Schumann, Thomas; Bräuer, G.; Skorupa, W.; Xiong, Shanxin; Wu, Chunyan; Gebel, T.

doi:10.12693/aphyspola.113.1273

Cited by 3 publications

(2 citation statements)

References 7 publications

(6 reference statements)

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“…A thicker polycrystalline tungsten foil of 9 µm + 25% thickness is used in SPONSOR. Commercial foils of this thickness are opaque and for this reason most suitable for a special flash lamp annealing (FLA) of the surface [7][8][9]. FLA offers a chance for the optimization of the moderator properties.…”

Section: Figmentioning

confidence: 99%

Design and Construction of a Slow Positron Beam for Solid and Surface Investigations

Anwand

Bräuer

Butterling

et al. 2012

DDF

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On the basis of the design and construction of the slow positron beam SPONSOR at the Helmholtz-Centre Dresden-Rossendorf an example is given how to build-up a simple slow positron beam for solid surface investigations within a short time and without high financial costs. The system uses a 22Na source and consists of three main parts: (1) the source chamber with a thin film tungsten moderator used in transmission, and a pre-accelerator stage, (2) the vacuum system with magnetic transport, a bent tube for energy selection and an accelerator, (3) the sample chamber with a sample holder, Ge detectors and (4) facilities for remote control and data acquisition. These parts are described in detail. The paper is preferentially addressed to beginners in the field of slow positron beam techniques and other readers being generally interested in positron annihilation spectroscopy.

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Section: Figmentioning

confidence: 99%

Design and Construction of a Slow Positron Beam for Solid and Surface Investigations

Anwand

Bräuer

Butterling

et al. 2012

DDF

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“…The flash--lamp annealing (FLA) systems are successfully used for silicon recrystallization in many laboratories [1,[7][8][9]. In principle, there is no sample size limitation for the FLA systems but producing a homogeneously annealed big area wafer (at least an eight inch one) is not trivial.…”

Section: Introductionmentioning

confidence: 99%

Solar Cell Emitters Fabricated by Flash Lamp Millisecond Annealing

et al. 2011

Self Cite

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Phosphorus ion implantation was used for the emitter formation in mono-and multicrystalline silicon solar cells. After ion implantation the silicon is strongly disordered or amorphous within the ion range. Therefore subsequent annealing is required to remove the implantation damage and activate the doping element. Flash-lamp annealing offers here an alternative route for the emitter formation at overall low thermal budget. During flash-lamp annealing, only the wafer surface is heated homogeneously to very high temperatures at ms time scales, resulting in annealing of the implantation damage and electrical activation of phosphorus. However, variation of the pulse time also allows to modify the degree of annealing of the bulk region to some extent as well, which can have an influence on the gettering behaviour of metallic bulk impurities. The µ-Raman spectroscopy showed that the silicon surface is amorphous after ion implantation. It could be demonstrated that flash-lamp annealing at 800• C for 20 ms even without preheating is sufficient to recrystallize implanted silicon. The highest carrier concentration and efficiency as well as the lowest resistivity were obtained after annealing at 1200• C for 20 ms both for mono-and multicrystalline silicon wafers. Photoluminescence results point towards P-cluster formation at high annealing temperatures which affects metal impurity gettering within the emitter.

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Millisecond annealing for advanced doping of dirty-silicon solar cells

Prucnal

Abendroth

Krockert

et al. 2012

Journal of Applied Physics

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Cost reduction is the overall goal in the further development of solar cell technologies. Multicrystalline silicon has attracted considerable attention because of its high stability against light soaking. In case of solar grade mc-Si, the rigorous control of metal impurities is desirable for solar cell fabrication. Although ion implantation doping got very recently distinct consideration for doping of monocrystalline solar material, efficient doping of multicrystalline solar material remains the main challenge to reduce costs. The influence of different annealing techniques on the optical and electrical properties of mc-Si solar cells was investigated. Flash lamp annealing (FLA) in the ms-range is demonstrated here as a very promising technique for the emitter formation at an overall low thermal budget. It could be presented that FLA at 1000 °C for 3 ms even without preheating is sufficient to recrystallize implanted silicon. The sheet resistance of FLA samples shows the values of about 50 Ω/sq. Especially, the minority carrier diffusion length for the FLA samples is in the range of 80 μm without surface passivation. This is up to one order of magnitude higher than that observed from rapid thermal annealing or furnace annealing samples. This technology shows great promise to replace the conventional POCl3-doping.

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Structural Changes in Flash Lamp Annealed Amorphous Si Layers Probed by Slow Positron Implantation Spectroscopy

Cited by 3 publications

References 7 publications

Design and Construction of a Slow Positron Beam for Solid and Surface Investigations

Design and Construction of a Slow Positron Beam for Solid and Surface Investigations

Solar Cell Emitters Fabricated by Flash Lamp Millisecond Annealing

Millisecond annealing for advanced doping of dirty-silicon solar cells

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