Theoretical and experimental comparison of contactless lifetime measurement methods for thick silicon samples

Schüler, Nadine; Hahn, Torsten; Dornich, K.; Niklas, J. R.; Gründig-Wendrock, B.

doi:10.1016/j.solmat.2010.02.028

Cited by 21 publications

(14 citation statements)

References 8 publications

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“…The transient PCD method is also used with other sensors, such as microwave PCD, having a history going back more than 50 years 5. Recent papers on these techniques are those given in References 6 and 7.…”

Section: Introductionmentioning

confidence: 99%

Contactless measurement of minority carrier lifetime in silicon ingots and bricks

Swirhun¹,

Sinton²,

Forsyth³

et al. 2010

Progress in Photovoltaics

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Measuring the bulk lifetime of unpassivated blocks and ingots is of great interest to the solar cell industry. The eddy‐current photoconductance method is a common choice for such measurements, employing the quasi‐steady‐state (QSS) mode for lower lifetime samples, and the transient photoconductance decay (PCD) mode for higher lifetime samples. Due to the high surface recombination velocity in unpassivated bulk samples, the lifetime measured with this method consists of components of recombination at both the surface and in the bulk. In order to determine the bulk lifetime from the measurement data, simulations of both transient and QSS mode measurements were conducted. Copyright © 2010 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Contactless measurement of minority carrier lifetime in silicon ingots and bricks

Swirhun¹,

Sinton²,

Forsyth³

et al. 2010

Progress in Photovoltaics

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“…MDP and QSSPC) is used. In an earlier publication the influence of different measurement regimes along with different laser wavelengths or doping concentrations on the measured lifetime was studied extensively by simulating the carrier profiles [9]. The results can be summarized as follows: an effective lifetime that is only lightly influenced by the surface can be obtained if a steady state photogeneration, a laser wavelength near 1100 nm and a small doping concentration is used.…”

Section: Inline Brick Measurementsmentioning

confidence: 99%

Next generation inline minority carrier lifetime metrology on multicrystalline silicon bricks for PV

Schüler

Mittelstraß

Dornich

et al. 2010

2010 35th IEEE Photovoltaic Specialists Conference

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In this paper the novel method MDP (microwave detected photoconductivity) [1][2][3][4] will be introduced to the field of contact less inline metrology at bricks. By the application of a widely advanced microwave detection technique, it is now possible to map minority carrier lifetime and photoconductivity simultaneously, with a so far unsurpassed combination of spatial resolution, sensitivity, and measurement speed. Beside these two parameters the iron concentration can be detected and analyzing the photoconductivity at steady state in comparison with the minority carrier lifetime, a lot of additional information can be derived. This paper will show first examples of minority carrier lifetime and photoconductivity maps, along with resistivity linescans and iron concentration maps of whole bricks measured inline. Furthermore simulations will be provided. Solving the transport equations for electrons and holes during the measurement at bricks, it can be proven that the measured effective lifetime deviates only lightly from the actual bulk lifetime. Furthermore it becomes clear that a steady state generation is more suited for brick measurements than non-steady state methods.

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“…Hence the surface influence decreases with increasing skin depth. In an earlier publication the influence of different measurement regimes along with different laser wavelength or doping concentrations on the measured lifetime was studied extensively by simulating the carrier profiles, that develop during a measurement [5]. Since MDP uses a steady state photo generation only this measurement regime is considered here.…”

Section: Theorymentioning

confidence: 99%

“…Since MDP uses a steady state photo generation only this measurement regime is considered here. Figure 2 displays the effect of the changing skin depth on the measured lifetime for different sample thickness, which was simulated as described in [5]. It is obvious that the measured lifetime is limited by the sample thickness and the skin depth of the microwave.…”

Section: Theorymentioning

confidence: 99%

High resolution inline detection of changes in the conduction type of multicrystalline silicon by contact less photoconductivity measurements

Schüler

Mittelstraß

Dornich

et al. 2010

2010 35th IEEE Photovoltaic Specialists Conference

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Changes in the conduction type of a multicrystalline brick can occur, since a high phosphorus concentration is typical for the low quality feedstock that is usually used in PV industry. The inline detection of these changes is made possible via photoconductivity measurements. The measured photoconductivity depends strongly on the resistivity of the sample. With a developed computer algorithm the sharp raises of the photoconductivity at pn-changes can be detected in bricks. With these measurements it is possible to detect pn-changes with a one mm resolution as early as possible in the production process.

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Theoretical and experimental comparison of contactless lifetime measurement methods for thick silicon samples

Cited by 21 publications

References 8 publications

Contactless measurement of minority carrier lifetime in silicon ingots and bricks

Contactless measurement of minority carrier lifetime in silicon ingots and bricks

Next generation inline minority carrier lifetime metrology on multicrystalline silicon bricks for PV

High resolution inline detection of changes in the conduction type of multicrystalline silicon by contact less photoconductivity measurements

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