Contactless measurement of minority carrier lifetime in silicon ingots and bricks

Swirhun, James S.; Sinton, Ronald A.; Forsyth, M.; Mankad, Tanaya

doi:10.1002/pip.1029

Cited by 43 publications

(28 citation statements)

References 5 publications

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“…1 A number of noncontact characterization techniques, such as microwave detected photoconductance decay (μ-PCD) 1,2 and inductively coupled quasi-steady-state photoconductance (QSSPC), 1,3 have been used for in-line monitoring of contamination and process induced modulation of electrical behaviors of Si. Steady state PCD measurement techniques 4 enabled by improved laser technology were recently introduced.…”

mentioning

confidence: 99%

“…Radiative recombination processes in Si and potential industrial applications of the PL characterization technique were discussed. For the characterization of electrical behaviors of Si, resistivity, carrier concentration, mobility and Hall effect measurements were routinely inspected during wafer fabrication and incoming quality control at the wafer fabs.1 A number of noncontact characterization techniques, such as microwave detected photoconductance decay (μ-PCD)1,2 and inductively coupled quasi-steady-state photoconductance (QSSPC), 1,3 have been used for in-line monitoring of contamination and process induced modulation of electrical behaviors of Si. Steady state PCD measurement techniques 4 enabled by improved laser technology were recently introduced.…”

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confidence: 99%

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Temperature Dependence of Photoluminescence Spectra from Crystalline Silicon

Yoo¹,

Kang²,

Murai

et al. 2015

ECS J. Solid State Sci. Technol.

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Photoluminescence (PL) spectra from lightly boron (B) doped p − -Si(100) under 488.0 nm Ar + ion laser excitation over the temperature range of 22 K-290 K is presented. Change of PL peak height (maximum intensity), peak position, peak area (areal intensity), full-width-at-half-maximum (FWHM: peak width) were determined as a function of temperature. PL intensity was sharply decreased with temperature increase in the temperature range of 22 K -170 K and then slowly increased again in the temperature range of 170 K-290 K. Phonon replicas of a relatively sharp band-to-band (or band edge (BE)) PL peak were clearly measured at low temperatures (≤90 K). PL spectra became broader and the phonon replicas were barely distinguishable as the temperature was increased. The envelope of the main PL peak and the broadening of peak width with the Si temperature were qualitatively in good agreement with the Maxell-Boltzmann probability distribution function. The direction of peak position shift with Si temperature change was also in good agreement with the temperature dependence of the Si bandgap. All measured PL spectra were curve fitted using combinations of modified Gaussian function(s) and standard Gaussian function(s). A simplified curve fitting method for broad PL spectra, consisting of the BE peak and band tail peak, using an exponentially modified Gaussian (EMG or ExGaussian) function and a number of standard Gaussian functions, was proposed from a practical usage point of view. Radiative recombination processes in Si and potential industrial applications of the PL characterization technique were discussed. For the characterization of electrical behaviors of Si, resistivity, carrier concentration, mobility and Hall effect measurements were routinely inspected during wafer fabrication and incoming quality control at the wafer fabs.1 A number of noncontact characterization techniques, such as microwave detected photoconductance decay (μ-PCD)1,2 and inductively coupled quasi-steady-state photoconductance (QSSPC), 1,3 have been used for in-line monitoring of contamination and process induced modulation of electrical behaviors of Si. Steady state PCD measurement techniques 4 enabled by improved laser technology were recently introduced.With the introduction of photoluminescence (PL) imaging and spectrum analysis, a noncontact, purely optical technique is now available for spatially resolved electrical characterization. For industrial applications, the ease of measurement without special sample preparation is important. This is especially true for in-line monitoring applications in semiconductor device manufacturers. PL measurements at room temperature (RT) are preferred. However, the RTPL spectra from Si are generally very broad and it is difficult to identify the origin of variations in RTPL spectra. In this paper, temperature dependence of PL spectra from lightly boron (B) doped p − -Si(100) was measured in the temperature range of 22 K-290 K and the effect of temperature on the change of PL spectra was investigated. Practic...

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mentioning

confidence: 99%

mentioning

confidence: 99%

Temperature Dependence of Photoluminescence Spectra from Crystalline Silicon

Yoo¹,

Kang²,

Murai

et al. 2015

ECS J. Solid State Sci. Technol.

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“…We find the analysis to be limited to about 0.1 μs in practice due to low SNR (0.1 suns, 30-s exposure). The calibration of a central high-lifetime grain with spectral PLIR can be verified with other techniques such as quasi-steady-state photoconductance (QSSPC) [19], dynamic PL [22], or full-spectrum PL measurements [56].…”

Section: A Quantitative Analysis Of Low-lifetime Bottom Section-extementioning

confidence: 97%

“…Only recently different approaches measuring lifetimes directly on the brick surface had been demonstrated. Two of them are based on the sensing of the photoconductance (PC) signal [19]- [21], while two others are based on photoluminescence (PL) techniques [22], [23]. Only PC measurements have been used for interstitial iron concentration measurements on brick level so far [20], [21].…”

mentioning

confidence: 99%

Imaging As-Grown Interstitial Iron Concentration on Boron-Doped Silicon Bricks via Spectral Photoluminescence

Mitchell

Macdonald

Schön

et al. 2014

IEEE J. Photovoltaics

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Abstract-The interstitial iron concentration measured directly on the side face of a silicon brick after crystallization and brick squaring can give important early and fast feedback regarding its material quality. Interstitial iron is an important defect in crystalline silicon, particularly in directionally solidified ingots. Spectral photoluminescence intensity ratio imaging has recently been demonstrated to independently provide high-resolution bulk lifetime images and is therefore ideally suited to assess spatially variable multicrystalline silicon bricks. Here, we demonstrate this technique to enable imaging of the interstitial iron concentration on boron-doped silicon bricks and thick silicon slabs. We present iron concentration studies for two directionally solidified silicon bricks of which one is a standard multicrystalline and the other is a seeded-growth ingot. This lifetime-based measurement technique is highly sensitive to interstitial iron with detection limits down to concentrations of about 1 × 10 10 cm −3 . Its accuracy is enhanced, as the injection level remains below 2 × 10 12 cm −3 during the measurement and, hence, avoids the influence of injection level dependences on the conversion factor, although it remains dependent on the knowledge of the electron capture cross section of interstitial iron in silicon. Access to both bulk lifetime and dissolved iron concentration provides a valuable parameter set of as-grown crystal quality and the relative recombination fraction of interstitial iron via Shockley-Read-Hall (SRH) analysis. Simulated interstitial iron concentration profiles support the presented experimental data.Index Terms-Bricks, dissolved iron, imaging, ingot, interstitial iron, photoluminescence (PL), silicon.

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“…The use of photoconductance (PC) measurements to determine the effective carrier lifetime τ eff in silicon samples is a well‐established experimental technique . This technique is also used for converting a measured photoluminescence (PL) signal into a spatially averaged absolute excess carrier concentration in PL measurements (quasi‐steady‐state PL and Suns‐PL ) and calibrating PL images to obtain quantitative carrier lifetime images .…”

Section: Scaling Factor Fs That Minimises Hysteresis Of τEff(δ N) Vermentioning

confidence: 99%

Impact of laterally non‐uniform carrier lifetime on photoconductance‐based lifetime measurements with self‐consistent calibration

Liang

Weber

Ren

2012

Progress in Photovoltaics

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The impact of laterally non-uniform carrier lifetime on the determination of the lifetime from photoconductance-based measurements, based on the self-consistent method proposed by Trupke and Bardos, is investigated using a simple model. It is shown that the method can result in an overestimation of the mean lifetime, with the magnitude of the error mainly dependent on the distribution of the effective lifetime across the area sensed by the photoconductance coil. Although in many cases the error introduced will be relatively small (in the order of 5% or less), much larger errors can result in some cases, such as for samples that feature small areas with a significantly higher than average lifetime. The error can be eliminated through independent measurement of the sample optical properties. Experimental measurements confirm the model predictions.

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Contactless measurement of minority carrier lifetime in silicon ingots and bricks

Cited by 43 publications

References 5 publications

Temperature Dependence of Photoluminescence Spectra from Crystalline Silicon

Temperature Dependence of Photoluminescence Spectra from Crystalline Silicon

Imaging As-Grown Interstitial Iron Concentration on Boron-Doped Silicon Bricks via Spectral Photoluminescence

Impact of laterally non‐uniform carrier lifetime on photoconductance‐based lifetime measurements with self‐consistent calibration

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