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Interpretation of time-of-flight (TOF)-SIMS spectra of organic molecules could be difficult because of the presence of a high number of secondary ion peaks; this often requires the use of data analysis methods to simplify the TOF-SIMS measurements. In this study, we will demonstrate that the gentle-SIMS method could be applied to more easily interpret the TOF-SIMS spectra of organic solar cell materials. Various conditions of the primary ion beam were used to generate the gentle-SIMS spectra from pure layers of two materials, i.e. PC70BM and PCDTBT. It will be shown that by using specific conditions of the primary ion column, the corresponding molecular ion or characteristic peaks of the pure organic materials are highlighted. Results obtained on an organic layer prepared from a mixture of both materials will be also discussed. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Although the use of cesium (or oxygen) primary ions in secondary ion mass spectrometry (SIMS) enabled its success in microelectronics, issues arise at ultra-low energies, as required for extreme depth resolution, as the sputter yield becomes very small such that one enters the regime of ion beam deposition instead of material erosion. A potential solution is then to lower the Cs supply by using a Cs/Xe co-sputtering as introduced by ION-TOF and explored extensively by J. Brison. In this work, we describe a somewhat similar implementation in a Cameca SC Ultra and assess its performance and impact on ion yields. Because of the specific Cameca instrumental configuration, one alternates with short time intervals between Cs+ and Xe+ primary ions in the same ion column. Depending on the time intervals used, this approach leads to either quasi-simultaneous sputtering (intervals ~80 ms) or sequential (intervals >1 s) sputtering. An exponential variation of the Si− yield is observed when the Cs beam fraction varies from 0 (Xe) to 1 (Cs) and is ascribed to the corresponding increase in the near surface Cs concentration, CCs. Moreover, we observed detailed timing effects of the beams implying that the same nominal CCs may lead to different secondary ion yields suggesting effectively a different CCs. These effects are further investigated by observing the finer details of Cs accumulation and migration mechanisms in situ. Finally, when analysing SiGe/Si layers, it is found that with increasing Cs/Xe ratio, the decay lengths tend to decrease whereas matrix effects at interfaces show an opposite trend. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We investigate the capabilities and limitations of performing (quantitative) in-depth composition analysis of polymer:fullerene blends, using time-of-flight SIMS with large Arn+ clusters. These blends constitute an important class of organic solar cell materials, whose performance and reliability critically depend on the blend's physicochemical properties at the nanoscale. We investigate the effect of Ar cluster size n, kinetic energy E and E/ n on the secondary ion and sputter yields and evaluate the Ar beam-induced damage in these layers. On the basis of this, the ideal experimental conditions are derived that allow us to investigate matrix effects and variations in sputter yields as function of polymer:fullerene compositions. We demonstrate that time-of-flight SIMS is capable to retrieve quantitative in-depth information in common polythiophene, polycarbazole, and fullerene blends. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The initial growth stages of boron-doped diamond, deposited by hot-filament chemical vapour deposition (HFCVD), are crucial for the conductivity of moulded tips used in scanning spreading resistance microscopy (SSRM) where the first grown layer is the active layer of the tip. In this paper, we investigate therefore the beginning of the growth by interrupting the HFCVD process for nano-crystalline (NCD) and microcrystalline diamond (MCD) films at various moments during the filament carburisation. The characterisation of these initial stages is done by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). A slow growth start after the first ∼20 min of carburisation is revealed by the change of C-bindings at the seed surface towards pure CC indicated by XPS. AFM measurements show that the actual growth starts after ∼40 min. Our work shows that boron tends to form BO clusters at the beginning of the growth (∼50 min) which can affect the conductivity of the first layers of our tips. By using carburised filaments the diamond seeds form earlier more pronounced crystal shapes which are related to a higher sp3/sp2 ratio. This is advantageous for moulded diamond tips used in electrical probing. [ABSTRACT FROM AUTHOR]

Several studies have been reported on the quantification of Ge in Si1-xGex using SIMS with oxygen or cesium primary ions. Most of them were limited to lower Ge concentrations. In this paper, we discussed procedures to quantify Ge content in Si1-xGex with x ranging from 0.11 to 0.70 by using low-energy Cs+ and O2+ primary beams. The results showed that at impact energy of 250 eV, the Ge secondary ion yield changed dramatically against the SiGe matrix composition with a Cs+ primary beam, whereas the change was minimal with an O2+ primary beam. As a result, quantification by using the reference signal inside Si substrate became difficult as no linear correlation exists between the Ge intensity and the Ge concentration in the case of Cs+ primary ions. However, the correlation between the ratios of secondary intensities I(Ge)/I(Si) within the SiGe layers and the composition ratio [Ge]/[Si] is monotonic (although nonlinear). Hence, quantification based on the ratios of the secondary ion intensities versus the ratios of the corresponding contents worked for both Cs+ and O2+ primary beams to quantify the Ge content of an unknown SiGe sample. In addition to this, we reported the angular (incidence angles between 0° and 70°) dependence of the sputter yield of SiGe as a function of Cs+ primary ion energy (150-500 eV). Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this study, the gentle SIMS (G-SIMS) method has been applied to organic solar cell materials. Various primary ion conditions were used to generate the G-SIMS spectra; monoatomic and cluster sources with different energies were tested. It is shown that the G-SIMS concept helps to identify both PCBM and P3HT materials through the enhancement of molecular and characteristic ions of the two molecules. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In order to minimize the considerable loss of Si material during the processing of a silicon photovoltaics (PV) substrate into a solar cell, the optimization of the saw damage (SD) removal is an important step. The PV cell process therefore requires a routine metrology solution suitable to probe the SD present in the substrate. Though cross-sectional Transmission Electron Microscopy is typically used for this purpose, this technique is not suited for in-line measurements. It is furthermore destructive, time-consuming and limited to very small sampling volumes. In this paper, we demonstrate the capabilities of the Photomodulated Optical Reflectance (PMOR) method for the in-line measurement of SD. PMOR is a laser-based pump-probe technique, wherein the probe laser measures the reflectance of the sample (DC reflectance) as well as the change in reflectance (AC reflectance) which the pump laser has induced by optically injecting excess carriers and heat. As PMOR is a local and nondestructive technique, it offers a very promising approach for the simultaneous characterization of roughness and SD. We demonstrate the versatility of this approach and the response of the DC and AC reflectances when studying wafers which have undergone successive etchings to remove the SD sequentially (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The characterization of Ni-silicides using electron energy loss spectroscopy (EELS) based methods is discussed. A series of Ni-silicide phases is examined: Ni3Si, Ni31Si12, Ni2Si, NiSi and NiSi2. The composition of these phases is determined by quantitative core-loss EELS. A study of the low loss part of the EELS spectrum shows that both the energy and the shape of the plasmon peak are characteristic for each phase. Examination of the Ni-L edge energy loss near edge structure (ELNES) shows that the ratio and the sum of the L2 and L3 white line intensities are also characteristic for each phase. The sum of the white line intensities is used to determine the trend in electron occupation of the 3d states of the phases. The dependence of the plasmon energy on the electron occupation of the 3d states is demonstrated. [ABSTRACT FROM AUTHOR]

Wet processes are gaining a renewed interest for removal of high-dose ion-implanted photoresist (II-PR) in front-end-of-line semiconductor manufacturing because of their excellent selectivity towards the wafer substrate and gate materials. The selection of wet chemistries is supported by an insight into the resist degradation by ion implantation. TOF-SIMS has been applied for characterization of the chemical changes in 248 nm deep UV photoresist after arsenic implantation. The cross-linking of the resist is dominant, especially for high doses and energies. It leads to significant depletion of hydrogen and formation of carbon macroradicals that recombine to form C-C cross-linked crust. A series of implanted samples were depth profiled using O2, Cs, C60 and an Ar-cluster beam as sputter species in order to analyze the chemical modifications inside the crust layer. Whereas in the implanted region, no sputter conditions providing molecular information have yet been identified, in the non-implanted region, many molecular ions are identified when profiling using Ar-clusters as sputter ions. Neither O2, Cs nor C60 sputtering would lead to molecular information in this region either. In particular with Ar-clusters, very large differences in sputter rates have also been observed between the implanted and non-implanted region, as well as a significant matrix effect in the implanted region. These differences are linked to the level of cross-linking present in the crust layer. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]