A5090224631- Silicon and Solar Cell Technologies
- Thin-Film Transistor Technologies
- Semiconductor materials and interfaces
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor materials and devices
- Silicon Nanostructures and Photoluminescence
- Advancements in Semiconductor Devices and Circuit Design
- Advanced Surface Polishing Techniques
- Silicon Carbide Semiconductor Technologies
- Electron and X-Ray Spectroscopy Techniques
- solar cell performance optimization
- Image Processing Techniques and Applications
- Photovoltaic System Optimization Techniques
- Infrared Target Detection Methodologies
- CCD and CMOS Imaging Sensors
Australian National University
2015-2024
Fraunhofer Institute for Solar Energy Systems
2022
Leibniz University Hannover
2022
University of Warwick
2016
University of Manchester
2016
It is known that the interstitial iron concentration in silicon reduced after annealing wafers coated with plasma-enhanced chemical vapour deposited (PECVD) nitride films. The underlying mechanism for significant reduction has remained unclear and investigated this work. Secondary ion mass spectrometry (SIMS) depth profiling of performed on annealed iron-contaminated single-crystalline passivated PECVD SIMS measurements reveal a high uniformly distributed This accumulation film matches loss...
Herein, a systematic study of the electronic quality gallium‐doped p‐type silicon wafers from Czochralski‐grown ingots with melt recharging is presented. It found that in as‐grown state, contain interstitial iron concentrations range 3 × 10 9 –2 cm −3 , trend slightly higher toward tail end each ingot, and subsequently grown ingots. However, analysis effective lifetimes indicates iron–gallium pairs are not dominant recombination centers state. Moreover, when these subjected to tabula rasa...
Abstract Heavily-doped, amorphous and polycrystalline silicon layers play important roles in solar cell fabrication performance. Here we demonstrate applications of time-resolved photoluminescence decay to measure recombination lifetimes such regions, which are generally below 1µs, difficult with other techniques. Firstly, the measurement Auger uniformly heavily-doped wafers, show impact surface samples phosphorus or boron doping concentrations 1×1019 cm-3. We also assess possible high iron...
Effective hydrogenation of interstitial iron in boron-doped multicrystalline silicon wafers is reported. The were annealed with plasma-enhanced chemical vapour deposited nitride films, at temperatures 400 °C – 900 and for times from minutes to hours. At low where a combined effect precipitation dissolved Fe expected, results show that the process dominates precipitation. concentrations reduce by more than 90% after 30-min anneal between 600 °C. most effective reduction occurs 700 °C, 99%...
In this work, we present a comprehensive re-evaluation of the iron–gallium (FeGa) recombination parameters in silicon using injection-dependent lifetime spectroscopy (IDLS). Ga-doped wafers (of varying resistivities) with precise concentrations intentional iron contamination wafer bulk, through ion implantation and distribution, were used. The presence interstitial Fei FeGa, their lifetime-limiting effects these wafers, confirmed measuring effective minority carrier changes during conditions...
The boron-oxygen recombination center responsible for the light-induced degradation of Czochralski silicon solar cells can be permanently deactivated by illumination at elevated temperature. In this study, we examine impact dopant compensation on deactivation process. experimental results show that rate depends inversely total boron concentration instead net doping concentration, suggesting is directly involved in A linear dependence activation energy further supports conclusion.
We investigate the impact of point-spread in silicon CCD sensor a BT Imaging LIS-R1 luminescence imaging system. It is found that an experimental definition function allows for significant restoration to be achieved. A comparison with short-pass filtering performed, demonstrating will still have measurable influence on image quality while reducing signal and increasing relative noise level. An implementation deconvolution presented at multi-crystalline grain boundary, illustrating practical...
Abstract Polycrystalline‐silicon/oxide (poly‐Si/SiO x ) passivating contacts for high efficiency solar cells exhibit excellent surface passivation, carrier selectivity, and impurity gettering effects. However, the ultrathin SiO interlayer can act as a diffusion barrier metal impurities this potentially slows down overall rate of poly‐Si/SiO structures. Herein, factors that determine blocking effects interlayers are identified investigated by examining two general types interlayers: 1.3 nm...
In this paper, we present measurements and modeling of the reduction in dissolved iron Fe; concentrations near grain boundaries multicrystalline silicon (mc-Si) wafers. The interstitial Fe are obtained via photoluminescence images taken before after iron-boron pair dissociation. A simple diffusion-capture model was developed to characterize removal by gettering sites. is based on a numerical solution 1-D diffusion equation with two fitting parameters: length atoms effective velocity at site....
We present experimental evidence for the impurity gettering effect of atomic layer deposited aluminium oxide (Al2O3) films on silicon wafers, during typical surface passivation activation at 425 °C. Iron was used as a model in to study effects. Dissolved iron concentrations were determined by carrier lifetime measurements, allowing loss kinetics wafers with Al2O3 coatings be monitored annealing. The redistribution layers and sub-surface regions examined secondary ion mass spectrometry depth...
In this paper, the precipitation kinetics of iron in multicrystalline silicon during moderate temperature annealing are systematically studied with respect to time, temperature, super-saturation level, and different types densities sites. The quantitative analysis is based on examining changes concentrations distributions interstitial wafers after at 400–700 °C. This achieved by using photoluminescence imaging technique produce high-resolution spatially resolved images concentrations. found...
The formation of certain types doped polysilicon passivating contacts for silicon solar cells is recently reported to generate very strong impurity gettering effects, revealing an important additional benefit this contact structure. This work investigates the underlying mechanisms by directly monitoring redistribution during and subsequent processes, via a combination secondary ion mass spectrometry (SIMS), transmission electron microscopy (TEM), minority carrier lifetime techniques....
Abstract We review recent results relating to the boron–oxygen defect in compensated crystalline silicon for solar cells. The experimental observations are not easily explained by standard model defect, which involves substitutional boron. In addition, proposed presence of boron–phosphorus pairs as a possible explanation these findings is inconsistent with numerous other results. A recently new based on interstitial boron, appears resolve problems. this paper we attempt extend case...
An assessment of the bulk material quality industrial Czochralski (Cz) grown phosphorus‐doped n‐type silicon (Si) wafers along an ingot is reported. The minority charge carrier lifetimes Cz‐Si wafer before and after phosphorous (POCl 3 ) diffusion gettering are assessed, by applying room‐temperature superacid surface passivation to avoid any additional or hydrogenation effect. A substantial increase in lifetime all observed, indicating effectiveness a step for such presence getterable...
We report luminescence phenomena from doped polycrystalline silicon (poly-Si) films and their applications to study carrier transport properties in passivating-contact solar cells. Low-temperature spectra emitted poly-Si layers are found be very broad stretched the crystalline (c-Si) peak significantly lower energies. This suggests that these contain radiative defect levels whose energies continuously distributed band edges deep bandgap. Moreover, photoinduced carriers inside completely...
Abstract We present high‐resolution images of the lateral distribution interstitial iron across wafers from various positions along length a directionally solidified multicrystalline silicon ingot. Iron were taken on in as‐cut state and also after two different phosphorus gettering steps performed at 845°C for 30 min, one with an additional anneal 600°C 5 h (referred to as extended gettering). The obtained by taking calibrated photoluminescence (PL) low injection carrier lifetimes, before...
Hydrogen-assisted defect engineering, via a hydrogenated silicon nitride (SiNx:H) capping layer, on doped polycrystalline (poly-Si) passivating-contact structures, is explored using complementary techniques. The hydrogen treatment universally improves the passivation quality of poly-Si/SiOx stacks all samples investigated. Meanwhile, their contact resistivity remains very low at ∼6 mΩ·cm2. Moreover, nature charge carrier recombination within poly-Si films also investigated by means...
Metallic impurities in the silicon wafer bulk are one of major efficiency-limiting factors solar cells. Gettering can be used to significantly lower metal concentrations. Aluminum oxide thin films from plasma-enhanced atomic layer deposition (PE-ALD) have been reported getter iron wafers. However, its gettering mechanism and kinetics remain unclear. In this study, by experimentally monitoring reduction bulk, aluminum is shown caused a segregation mechanism. Fitting experimental simulation...
The removal of dissolved iron from the wafer bulk is important for performance p-type multicrystalline silicon solar cells. In this paper we review some recent progress in understanding both external and internal gettering iron. Internal at grain boundaries dislocations occurs naturally during ingot cooling, can also be driven further cell processing, especially by moderate temperature anneals (usually below 700 °C). intra-grain defects plays key a role such precipitation annealing. External...