TY - THES ID - 135461535 TI - Qualitative and Quantitative analysis of compound semiconductors using Atom Probe Tomogaphy AU - Kumar, Arul. AU - Vandervorst, Wilfried. AU - KU Leuven. Faculty of science. Department of physics and astronomy PY - 2016 PB - Leuven Faculteit wetenschappen DB - UniCat UR - https://www.unicat.be/uniCat?func=search&query=sysid:135461535 AB - Current state of the art electronic devices are nanoscaled, three-dimensional and employ compound semiconductors like SiGe, InP, InGaAs etc. as the active components. The metrology requirements for these devices are structural and elemental analysis in three-dimensions with sub-nanometer resolution. Laser assisted Atom Probe Tomography (L-APT) is one metrology tools that fulfills this criteria and is being developed actively for routine analysis of semiconductor devices. In this thesis, we evaluate and develop L-APT for qualitative and quantitative analysis of compound semiconductors. To do this, we identified two main focus areas, firstly improve the understanding of the interaction between the laser and the semiconducting specimen and secondly develop and apply statistical data mining approaches to understand the impact of physical mechanisms like cluster formation on material properties.It is well known that the pulsed laser generates a thermal pulse in the specimen. We developed a new method to quantify the temperature at the apex of the semiconducting specimen. A major advantage of the proposed method is that the determined temperature value is a function of derivatives, thereby keeping the error low. Subsequently, we used the method to gain insight into the impact of the laser on the apex shape of moderately absorbing materials (e.g. Si under green illumination) and laser absorption by a-priori non-absorbing materials (e.g. absorption of 515 nm laser by GaN). In this work we will show that the apex shape is a function of both the absorption depth and the spatial distribution of the resonantly coupled light. In situations when the light couples in close proximity to the apex of the tip, minimal diffusion of the locally generated heat occurs before field evaporation, leading to an asymmetrical apex shape. The non-hemispherical shape in turns degrades spatial resolution due to magnification variations across the apex. Regarding the absorption by a-priori transparent samples, we observed that amorphized shell created due to the Ga ion beam damage during sample preparation is highly absorptive and plays a vital role in laser absorption. In this work we used L-APT to understand the role of Sn clusters formation in layer relaxation of Ge(1-x)Sn(x) layers. To do this, we first verified the absence of field and laser induced artifacts in the reconstructed layers and also developed a new cluster analysis algorithm to extract ultra-fine scaled clusters (few 10's of atoms). We will demonstrate that Sn cluster formation is not the dominant relaxation mechanism in layers relaxing due to its thickness or due to a post growth thermal anneal and defect generation is potentially the main cause of relaxation. ER -