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AIP Conference Proceedings [Author(s) SILICONPV 2018, THE 8TH INTERNATIONAL CONFERENCE ON CRYSTALLINE SILICON PHOTOVOLTAICS - Lausanne, Switzerland (19–21 March 2018)] - Atom probe Tomography of fast-diffusing impurities and the effect of gettering in multicrystalline silicon
摘要： This article demonstrates an approach for multiscale characterisation of individual defects, such as grain boundaries, in multicrystalline silicon. The analysis techniques range from macroscale characterisation of average bulk lifetime, through photoluminescence to resolve spatial recombination, and finally to nanoscale analysis of the crystallographic characteristics and impurity decoration of the grain boundary using Transmission Kikuchi Diffraction and Atom Probe Tomography. This method can be used to characterise defects and their response to processing, such as gettering and hydrogen passivation. In this paper it is applied to the test case of Saw Damage Gettering on Red Zone High Performance Multicrystalline Silicon. In both as-cast and gettered samples, copper and chromium were observed at a recombination active, random angle grain boundary. After gettering the copper excess was found to decrease. In contrast, the slower diffusing chromium was found to increase, potentially indicating internal gettering. At a recombination inactive Σ3 grain boundary only oxygen was observed at the boundary before gettering, with no transition metals detected.
关键词： multicrystalline silicon,grain boundaries,gettering,impurities,Atom Probe Tomography
更新于2025-11-21 11:20:48
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<i>(Invited)</i> Proximity Gettering Design of Hydrocarbon Molecular Ion Implanted Silicon Wafers Using Direct Bonding Technique for Advanced CMOS Image Sensors: A Review
摘要： We developed high gettering capability silicon wafers for advanced CMOS image sensors using hydrocarbon molecular ion implantation and surface activated direct wafer bonding (SAB). We found that this novel wafer has three unique characteristics for the improvement of CMOS image sensor device performance. The first is metallic impurity gettering capability in the hydrocarbon ion implantation projection range during CMOS device fabrication. The second is the oxygen out-diffusion barrier effect; this wafer can control out-diffusion to the device active region from the CZ grown silicon substrate during CMOS device heat treatment. The third is the hydrogen passivation effect; hydrogen passivates to the Si/SiO2 gate oxide interface state defects which out-diffuse to the device active region from the hydrocarbon ion implantation projection range during the CMOS device fabrication. Moreover, we demonstrated that this novel wafer can improve the pn-junction leakage current under the actual device fabrication.
关键词： CMOS image sensors,hydrocarbon molecular ion implantation,surface activated direct wafer bonding,gettering capability,oxygen out-diffusion barrier,hydrogen passivation
更新于2025-09-23 15:21:21
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Impact of pre-fabrication treatments on n-type UMG wafers for 21% efficient silicon heterojunction solar cells
摘要： Silicon heterojunction solar cells achieve high conversion efficiency due to the excellent surface passivation provided by the hydrogenated intrinsic amorphous silicon films. However, they require a high-quality wafer as a starting material because their low-temperature processing does not allow for gettering. Czochralski-grown upgraded metallurgical-grade (UMG-Cz) silicon is a low-cost alternative to electronic-grade silicon for silicon solar cells, but is often limited in lifetime by grown-in defects. We have previously shown that pre-fabrication treatments, namely tabula rasa, phosphorus diffusion gettering, and hydrogenation, can significantly improve the bulk quality of UMG-Cz wafers. These help to mitigate the impact of grown-in oxygen precipitate nuclei and metallic impurities. In this work, we fabricate rear-junction silicon heterojunction solar cells on both as-grown and pre-treated UMG-Cz and electronic-grade wafers. We show that pre-fabrication treatments have a marked impact on solar cell efficiencies. With pre-fabrication treatment, the efficiency improves from 18.0% to 21.2% for the UMG-Cz cells and 21.2%–22.7% for the electronic-grade cells. Comparison of the open-circuit voltages of the as-grown and pre-treated UMG-Cz and electronic-grade cells using Quokka simulations reveals that the bulk lifetime remains the primary limiting factor for the UMG-Cz wafers.
关键词： Hydrogenation,Phosphorus diffusion gettering,Czochralski silicon,Solar-grade silicon,Tabula rasa,Silicon heterojunction solar cells
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Gettering efficacy of an APCVD glasses based stacked co-diffusion for bifacial mc-Si PERT solar cells
摘要： Gettering of impurities is an important task in p-type mc-Si solar cell production. Phosphorus diffusion via POCl3 is currently the most common way to achieve this. We report about the gettering efficacy of a co-diffusion in which POCl3 is not used. Phosphorus and boron containing glasses are both deposited prior to the diffusion via atmospheric pressure chemical vapor deposition (APCVD). The presented APCVD glasses based co-diffusion allows a loading without spacing and therefore has the potential for a very high throughput. As we demonstrate in this work, the overall gettering efficacy in different kinds of stacks is similar to the gettering efficacy in non-stacked APCVD glasses based diffusions. The reduction of interstitial iron in the analyzed lifetime samples is ascribed to phosphorus diffusion gettering and works in stacks just as well.
关键词： co-diffusion,Gettering,PERT solar cells,APCVD,mc-Si
更新于2025-09-16 10:30:52
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Substrate integrated waveguide‐slot wide‐angle scanning aperiodic phased array with low side‐lobe levels
摘要： The concentrations of Cr, Fe, Ni, and Cu in a cast-monocrystalline silicon ingot grown for solar cell applications are reported. Wafers taken from along the ingot are coated with silicon nitride ?lms and annealed, causing mobile impurities to be gettered to the ?lms. Secondary ion mass spectrometry is applied to measure the metal content in the silicon nitride ?lms. The bulk concentrations of the gettered metals in samples along the ingot are found to be: Cr (3.3 (cid:1) 1010–3.3 (cid:1) 1011 cm(cid:3)3), Fe (3.2 (cid:1) 1011–2.5 (cid:1) 1012 cm(cid:3)3), Ni (1.5 (cid:1) 1012–1.3 (cid:1) 1013 cm(cid:3)3), and Cu (7.1 (cid:1) 1011–3.2 (cid:1) 1013 cm(cid:3)3). For each metal, the lower limit is measured on the wafer from the middle of the ingot, and the higher limit is measured on wafers from the bottom or the top. The results are compared with similar data recently measured on a high-performance multicrystalline silicon ingot. The results provide insights into the total bulk concentrations of the metals in cast-grown ingots.
关键词： gettering,transition metals,cast-mono,silicon nitride
更新于2025-09-11 14:15:04