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Nanoelectronics relies more and more on novel materials and architectures for technology advancements in terms of power, cost and area. The device functionalities depend on the composition and the amount of impurities of the device materials, whereby controlling the concentrations with high accuracy is essential to tailor the device performances. Besides, it is crucial to characterize devices with relevant dimensions and substrates as it is demonstrated that compositions may be size dependent, and atom areal densities may be substrate dependent. Ion beam analysis, in particular elastic recoil detection (ERD) and Rutherford backscattering spectrometry (RBS), is recognized to offer compositional quantification as a function of depth in the target. However, in ion beam analysis, mass and depth resolutions are limited by the detector performance. Lateral resolution is hampered by the broad primary beam dimensions, whereby conventional RBS analyses are on blanket layers. Sensitivity to atom areal densities is limited by the counting statistics and background noise.The objective of this thesis work is to extend ion beam analysis towards next generation nanoelectronics devices through four major advancements, namely high mass resolution, sensitivity, lateral and depth resolution.The mass resolution in elastic recoil detection is limited by the detector resolution performance, whereby neighboring elements in the periodic table have overlapping recoil distributions. This hampers the quantification of the atom areal densities for recoils with small mass difference. A mass discrimination procedure is developed which deconvolves the overlapping recoil signals. We show that 1 amu mass resolution in ERD can be attained with the mass discrimination algorithm.In Rutherford backscattering spectrometry, the sensitivity to low amounts of materials is enhanced by reducing the background due to pile-up effects, hence by increasing the signal-to-noise ratio. Pile-up background strongly depends on the count rate, whereby improving this background requires low count rates. The count rate is reduced either through the segmentation of the detector active area and the data acquisition by multiple devices or through the dispersive power of a magnetic spectrometer used to deviate the substrate signal outside of the detector area, thus suppressing the dominant backscattering yield in a conventional RBS spectrum. With such advancements, it is feasible to probe the defectivity at the early stages of area selective atomic layer depositions on plasma treated substrates.Furthermore, RBS is extended towards the analysis of confined nanostructures with lateral dimensions of as low as 16 nm. The broad beam is utilized to probe simultaneously a multitude of periodically repeated nanostructures embedded in a foreign matrix, whereas the mass difference between the elements in the fins and in the matrix is used to isolate the information from the nanostructure. The extracted compositions average over the ensemble of probed devices, thereby providing a statistically relevant analysis.Finally, the RBS depth resolution is conventionally limited at 10-15 nm by the detector energy resolution. In a magnetic spectrometer, ions are spatially dispersed as a function of their magnetic rigidities, thus energies, whereby high energy resolution is enabled by a position sensitive detector which records the ion position on the focal plane with high spatial resolution.The superior energy resolution allows a depth resolution of 2.7 nm of cobalt. When the detector resolution is improved, other sources of energy broadening must be considered, namely the primary beam broadening, the geometrical broadening and the energy spread induced by sample modifications. These contributions are discussed and improvements are proposed to minimize the energy broadenings towards high energy resolution.

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Introduction of 3D device structures, such as fin field effect transistors (FinFETs), nanowire based transistors and novel materials is inevitable to sustain scaling and continuous performance improvement in future technology. The gate stacks of 3D structures consist of non-planar layers; some of which have a sub-nanometer thickness. Their development and understanding is intimately linked with the ability to obtain information on their structure, composition and dopant distribution. The latter is a complex task as these structures have nanometer scale dimensions and are composed of heterogeneous materials including insulators. Therefore, metrology tools must be developed that are capable of measuring these structures at near atomic scale and in particular be able to perform 3D elemental mapping of their chemical distributions with sub-nanometer resolution.The objective of this thesis is therefore to establish a technique capable of compositional characterization of 3D-nanostructures using the Atom Probe Tomography (APT) with a focus on the analysis of FinFETs. APT works on the basis of peeling of ionized atoms from a needle shaped specimen and projected onto a position sensitive single ion detector. The process of peeling off ionized atoms from the surface of a solid is called field evaporation. In APT, field evaporation is achieved by applying a standard voltage of several (positive) kilo-volt to the needle shape specimen (APT-tip) with an apex radius of 10-100 nm. This creates an electric field of several 10 V/nm around the tip enabling the ionization of atoms on the surface of the tip. The positive ions thus created are repelled from the surface by the electric field and follow a trajectory pointing perpendicularly away from the surface. These ions are projected on to a position sensitive detector which is a few centimeters away from the tip apex. This approach allows us to magnify the atomic positions on the surface of detector by more than a million times enabling sub-nanometer lateral resolution. The reconstruction of the evaporated ion will be performed by using projection principle, which is accurate enough to reconstruct with sub-nanometer precision.This work demonstrated the capability of laser assisted wide angle tomographic atom probe (LAWATAP) to characterize 3D structures like FinFETs with near atomic resolution. In the discussion of optimization of sample preparation (using focused ion beam), an explanation has been provided for the necessity to avoid Ga+ beam interaction as it destroys the region of interest during the sample preparation for 2D and 3D device structures. The results in this study have highlighted in depth understanding of the 3D dopant distribution in nanoscaled devices (FinFETs). Therefore, it is concluded that laser assisted APT to date provides 3D atomic scale mapping of nanoscale semiconductor devices in its current state.

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Organic semiconductor devices have received an enormous amount of research interest, leading to their successful commercialization. Blend and doped layers are becoming increasingly ubiquitous in organic electronic devices. In order to better understand the efficiency and reliability of these devices, there is a growing need for quantitative analysis of these layers. ToF-SIMS using cluster ion beams has routinely been employed to obtain molecular depth profiles of organic layers. Yet, quantitative analysis using these molecular ions has remained challenging. Largely responsible for the notoriety in compositional depth profiling are chemical ‘matrix’ effects which impact the ionization of molecular species. In this thesis, we present a thorough physico-chemical analysis of organic semiconductor layers. An obvious pre-requisite here is to preserve molecular information throughout the depth of these layers. In order to ensure this, one has to make an educated choice of beam parameters such as the energy and size of the clusters being used. For achieving an understanding of the chemical effects induced by the sputtering beam, we perform statistical analysis of the spectra. This statistical analysis in combination with studying the sputtering yields provides important insights into the cross-linking caused by ion beams with a relatively high energy per atom in the cluster. Further, we study the evolution of the sputtering yield with respect to the composition of blend layers. To study and quantify the matrix effects observed in blend layers, we propose an alternative approach through a quantity we call the fractional secondary ion yield. The advantage of this approach over using ion intensities is that the quantifying parameters can be correlated with the chemical properties of the matrix. In order to demonstrate the generality of this approach, we extend it to doped organic layers. The results indicate that using fractional secondary ion yields may indeed provide a more cogent quantification of the matrix effects in such layers. Additional to the chemical matrix effects on the secondary ion intensities, we observe strong ionization effects on molecular ions at the interface. We explore the charge transfer arising from energy level alignment at the interface between the organic material and the substrate as an explanation of the observed intensity enhancements. This explanation has been demonstrated to be applicable on blend and pure layers of the organic semiconductors used in this study.

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With the continuous downscaling of the complementary metal oxide semiconductor (CMOS) devices in past years the need for two-dimensional (2D) characterization techniques has greatly increased as well. The latter are required to accurately profile the 2D dopant/carrier distributions in very short channel devices as small variations in these distributions have a profound impact on the device behavior. The scanning spreading resistance microscopy (SSRM) has emerged as a powerful tool through its demonstrated capabilities to profile carrier distributions in 2D with high spatial resolution and doping sensitivity. The SSRM metrology concept creates therefore new possibilities for technology computer aided design (TCAD) engineers to develop, verify and calibrate advanced physical models for high predictability of future devices. Now a days only one-dimensional (1D) characterization techniques such as secondary ion mass spectrometry (SIMS) and spreading resistance profiling (SRP) are extensively used for validating and calibrating the process models. These are, however, no longer sufficient for semiconductor devices with small dimensions.The objective of this thesis, therefore, is to demonstrate the potential of the 2D SSRM metrology concept in improving TCAD modeling, through the validation of the accuracy requirements for the SSRM measured 2D profiles that can provide a useful feedback to TCAD simulations. In this thesis two approaches have been presented. In the first approach we illustrate how high-resolution 2D-carrier profiles from SSRM can be used to calibrate process simulations for the accurate prediction of the device performance. This approach has been demonstrated on p-MOSFETs exhibiting low doping concentrations that cause extensive mobile carrier diffusion, which needs to be taken into account while calibrating the process/device simulations. As calibrating process models remains a very complex and time-consuming procedure, we also introduce a second approach where we directly incorporate SSRM measured 2D-carrier profiles into a device simulator circumventing the calibration step of the process simulations. With this approach the device results can be interpreted directly based on the real 2D-carrier profiles. In both approaches we validate the accuracy of the SSRM 2D-profiles that makes the SSRM the most relevant metrology concept to provide a feedback to TCAD process and device simulations.