Scanning Photoluminescence for Wafer Characterization

Higgs, V.; Chin, Fun Tat; Wang, Xue Cheng

doi:10.4028/www.scientific.net/ssp.63-64.421

Cited by 9 publications

(5 citation statements)

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“…Several such techniques in use today include the surface photovoltage (SPV) and photoconductive decay (PCD) methods, which are sensitive to the total number of recombination centres in the bulk and at the surface of a wafer. A new approach to lifetime monitoring is offered by photoluminescence (PL) mapping at room temperature [2,3]. This can be performed with a high lateral resolution of a few micrometres.…”

Section: Introductionmentioning

confidence: 99%

Defect monitoring using scanning photoluminescence spectroscopy in multicrystalline silicon wafers

Ostapenko

Tarasov

Kalejs³

et al. 2000

Semicond. Sci. Technol.

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Scanning photoluminescence (PL) spectroscopy was performed on as-grown and processed multicrystalline silicon (mc-Si) wafers to investigate the defect distribution affecting the efficiency of solar cells. In highly inhomogeneous mc-Si prepared by (i) edge-defined film-fed growth or (ii) a block-casting technique, regions of a wafer with enhanced recombination activity and reduced minority carrier lifetime exhibit an intensive 'defect' PL band at room temperature with the maximum at about 0.8 eV. By comparing PL mapping with the distribution of dislocations, we present experimental evidence that the 0.8 eV band corresponds to electrically active dislocation networks. This was confirmed using low-temperature PL spectroscopy, which revealed a characteristic quartet of the dislocation D-lines. One of these dislocation lines, D1, can be tracked as temperature increases and linked to the 'defect' band. Strong linear polarization of the 0.8 eV PL band corresponds to a preferential localization of defects in regions with a high level of elastic stress measured with scanning infrared polariscopy. The origin of the 0.8 eV PL band is attributed to dislocations contaminated with impurity precipitates.

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Section: Introductionmentioning

confidence: 99%

Defect monitoring using scanning photoluminescence spectroscopy in multicrystalline silicon wafers

Ostapenko

Tarasov

Kalejs³

et al. 2000

Semicond. Sci. Technol.

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“…This is an important characteristic of carrier-density-wave methodologies, compared to dc PL which relies on magnitude contrast: it has previously been suggested that contrast variation with modulation frequency is a result of the frequency dependence of the carrier injection level, which is controlled by the ac carrier diffusion length. 32 While the concentration of carriers relative to the defect density will undoubtedly play a role in altering the carrier recombination dynamics, especially at high injection levels, the present PCR experimental results and simulations strongly sug-gest that the primary source of contrast with modulation frequency is the relation between the modulation period and the lifetime. This relationship can be physically understood in terms of the primary antinode of a carrier-density standing wave across the thickness of the semiconductor region which exhibits an approximate equality between modulation period and recombination lifetime as a kind of carrier diffusion-wave resonance phenomenon.…”

Section: Recombination Lifetime and Depth-profilometricmentioning

confidence: 71%

Electronic Defect and Contamination Monitoring in Si Wafers Using Spectrally Integrated Photocarrier Radiometry

Shaughnessy

Mandelis

2006

J. Electrochem. Soc.

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The ability of spectrally integrated room-temperature photocarrier radiometry to image electronic defects and contamination in silicon wafers is presented. Amplitude and phase imaging contrast is a result of signal sensitivity to local variations in the recombination lifetime of photoexcited carriers. Experimental frequency scans are fitted to carrier density-wave theory to simultaneously obtain the recombination lifetime, diffusivity, and surface recombination velocities ͑front and back͒. Lifetime measurements are combined with lateral surface scans to produce quantitative lifetime imaging. Contaminated boron-doped silicon wafers with iron concentration ϳ10 11 cm −3 on a baseline of ϳ5 ϫ 10 9 cm −3 have been successfully imaged and exhibit a much higher spatial resolution than surface photovoltage images. Recombination lifetime measurements before and after photodissociation of FeB pairs have been utilized for quantitative determination of iron concentration; however, lifetime accuracy limitations due to photodissociation by the excitation laser under medium-to-high optical injection levels required for photocarrier radiometric measurements compromise the accuracy of heavy ion ͑Fe͒ concentration measurements.

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“…Also although the contamination levels in state of the art processing are very low, slip formation will act as a perfect nucleation site for any residual impurities, which can be gettered, and these impurities produce electrical activity. Also we have already shown that this technique is extremely sensitive and can detect defects whose recombination properties are controlled by shallow levels, which cannot be detected by EBIC at room temperature [21]. Further experiments are under way to clarify the activity of slip defects using combined TEM/EBIC and PL mapping.…”

Section: Discussionmentioning

confidence: 95%

“…It therefore follows that defects are revealed due to their impurity decoration and the true nature of the defect may not be apparent. However, because the defect co-ordinates are known, the defect location can be precisely located using laser marking to facilitate TEM analysis to fully identify the defect [21].…”

Section: Discussionmentioning

confidence: 99%

Photoluminescence characterization of defects in Si and SiGe structures

Higgs

Chin

Wang

et al. 2000

J. Phys.: Condens. Matter

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Low-temperature photoluminescence (PL) spectroscopy is a very sensitive tool to investigate the presence of dislocations in Si. The main dislocation-related bands (D1-D4) have been attributed to a wide range of causes, either intrinsic properties of the dislocation or impurity related. PL is a competitive recombination process and the non-radiative processes need to be measured to understand the overall effect of impurities. PL spectroscopy samples a large volume in comparison to the dislocation itself and therefore gives an average effect. High-resolution room-temperature PL mapping (SiPHER) has been used to detect defects in both Si and SiGe wafers. Whole-wafer PL maps reveal the presence of slip on 300 mm Si wafers. Comparison studies with defect etching show that there is a one-to-one correlation between defects detected in the PL micro-scans and those revealed by defect etching. Whole-wafer mapping has revealed a number of different defect types in SiGe epilayers. The ability to record whole-wafer PL maps facilitates the rapid identification of inhomogeneities and defects. High-resolution PL micro-maps showed the defect area to contain a high density of misfit dislocations, and the nucleation site has strong non-radiative recombination. One common defect type was analysed using plan view transmission electron microscopy (TEM) and optical microscopy; these results revealed the presence of a high density of defect loops and stacking faults consistent with the high recombination rate at the defect site.

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Scanning Photoluminescence for Wafer Characterization

Cited by 9 publications

References 0 publications

Defect monitoring using scanning photoluminescence spectroscopy in multicrystalline silicon wafers

Defect monitoring using scanning photoluminescence spectroscopy in multicrystalline silicon wafers

Electronic Defect and Contamination Monitoring in Si Wafers Using Spectrally Integrated Photocarrier Radiometry

Photoluminescence characterization of defects in Si and SiGe structures

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