Title Promoter Affiliations Abstract "Interface Engineering for Performance Enhancement in 2D Field Effect Transistors" "Marc Heyns" "Surface and Interface Engineered Materials (SIEM)" "2-dimensional (2D) semiconductors such as 2D transition metal dichalcogenides (MX2) have recently drawn much attention in the field of nano-electronics due to their potential for superior electrostatic control and heterogeneous integration. However, current MX2 devices suffer from high source and drain contact resistance, high defect density and low capacitance/charge build-up in the channel. To mitigate these challenges, it would be beneficial to place emphasis on the 2D form factor in the device design, to fully utilize the structural advantages such as atomic-layer construction, periodicity, polarity as well as grain crystallinity and grain boundary to improve contact, transport and gating while down-scaling the device dimension. The objective of this Ph D research is to demonstrate nano-scale devices using 2D materials as channels, contacts and dielectric surroundings; to experimentally explore the performance and scaling potentials of the 2D materials metal-oxide-semiconductor field-effect transistor (MOSFET). On the 2D channel we will investigate the impact of grain boundaries and Lg scaling. For contact resistance study we will implement edge contact schemes, including metal-MX2 and graphene-MX2 edge contacts to explore and examine the 2D form factor. For gate stack study, besides interface trap density (Dit) reduction, we will investigate the role of the van der Waals gap between the 2D channel and the gate dielectric and attempt to mitigate its impact on EOT with combinations of MX2/2D-dielectrics (h-BN, h-AlN, GaN*) and potentially MX2/ferroelectric oxides.  *Nature Materials 15, 1166–1171 (2016) “Two-dimensional gallium nitride realized via graphene encapsulation”" "Modeling of the tunnel field-effect transistor." "ESAT - MICAS, Microelectronics and Sensors" "The nanowire-based tunnel field-effect transistor (tunnel-FET) is a promising candidate to replace the metal-oxide-semiconductor field-effect transistor. Due to the absence of a limit on the subthreshold swing, the tunnel-FET allows a reduction of the supply voltage below the 1 V plateau. The perspective of such a breakthrough results in a strong worldwide interest in the tunnel-FET. Despite the expanding research domain and out own important conceptual contributions, the physical insight in the tunnel-FET performance is still very primitive and the developed models are based on very simplified configurations. The purpose of this project is the further development of a model for the tunnel-FET performance. The project is focused on the incorporation of realistic fabrication parameters (like e.g. doping gradients) or circuit parameters (like e.g. drain voltage) in the model, as well as the exploration of non-conventional configurations." "Diamond-based junction field-effect transistor for extreme power applications" "Paulius POBEDINSKAS" "Materials Physics" "This research project brings together the fields of synthesis and characterization of doped diamond together with the fabrication of devices adapted for high-power electronics. We aim to (i) investigate B- and P-doped diamond films grown on diamond substrates with different crystallographic orientations in order to reduce the defect density in the grown layers, and (ii) to utilize these diamond films in fabricating and characterizing junction-gate field-effect transistors (JFETs). The prototypes are based on a stacked structure composed of B- and P-doped diamond films. First, the laterally grown P-doped diamond layers will be characterized with respect to their defects and electrical properties, which later will be correlated with the performance of the JFETs. Second, various fabrication techniques will be implemented to achieve the proposed JFET architecture. Finally, charge transport mechanisms and properties of the devices will be studied to evidence their outstanding performance." "Integration of a IIIV p-channel tunnel-field-effect transistor for ultra-low power nano-CMOS applications." "Marc Heyns" "Surface and Interface Engineered Materials" "The Tunneling Field-Effect Transistor (TFET) is a promising candidate for future low-power logic applications. The carrier injection mechanism of the TFET is quantum mechanical Band-To-Band Tunneling (BTBT), which is accompanied by an energy filtering mechanism. This filtering allows switching from the off-state to the on-state using a lower supply voltage than the MOSFET, and hence reducing the power consumption of integrated circuits.To identify favorable III-V TFET configurations and guide TFET fabrication, semi-classical and quantum mechanical simulations are crucial. However, there is uncertainty on the accuracy of the models relevant to TFET and on their input parameters. The topic of this thesis is the experimental calibration of the models for the desired BTBT as well as the ones of relevant parasitic mechanisms, like Shockley-Read-Hall and trap-assisted tunneling due to bulk traps. We also characterize Field-Induced Quantum Confinement (FIQC) and the energy band alignment of heterojunction TFET. We achieve this using tunnel diodes and MOS capacitors, which are easier to fabricate and characterize than complete TFETs. Our work enables improved understanding of experimental TFET data and more accurate performance prediction of III-V heterojunction TFET." "Oxide semiconductor of select transistor for memory devices" "Valeri Afanasiev" "Semiconductor Physics" "Amorphous metal oxide semiconductor like Indium-Gallium-Zinc-Oxide (IGZO) is the most commonly used oxide material in display application due to their field-effect mobility, good uniformity over large glass substrates sizes and low temperature process.Besides driving innovative thin-film transistors for display applications, IGZO is also seen as a strong candidate for replacing silicon in some architectures, helping the semiconductor industry to boost the scaling by placing the transistors in the Back-End-Of-Line of a chip rather than in the periphery. For example, thanks to its extremely low leakage current and its relatively good carrier mobility, IGZO TFT used as selector can make DRAM memories more power efficient while maintaining the data writing and reading at very high speed. In addition, channel material IGZO can be formed at a relatively low temperature, making it conducive for fabrication in stack array. Integration of such material in DRAM cell architecture opens up the possibility of 3D DRAM integration, which helps to continue the DRAM scaling roadmap. Our goal is to explore new schemes and improved material processing in order for IGZO devices to become practical in DRAM application." "Photonic colloidal crystals: How do salt types, combined with electric field, change colloidal structure formation?" "Koen Clays" "Molecular Imaging and Photonics" "Photonic colloidal crystals: How do salt types, combined with electric fields, change colloidal crystal structure formation? Colloidal particles and their self-assembly into an ordered structure play an important role in the formation of photonic crystals that can have a diverse range of uses such as optical transistors, smart shock absorbers or as a part of electronic paper [1,2]. However one of the main difficulties is related to the fact that formation of well-ordered, defect free large domain 3D crystal structures is extremely difficult task [3,4]. Up to date different techniques were used for 3D crystal formation such as vertical self-assembly, spin-coating, dielectrophoretic field and gravitational field application - that have each been successful only in producing face centred cubic (FCC) structures. Lack of the possibility to manipulate and control crystal packing and therefore the photonic band gap is essential limitation for the wide range of applications [5-7]. In this proposal we would like to suggest the idea of exploring the influence of different anions (SO42-, Cl- and NO3-) on colloidal particles packing on various hydrophobic surfaces (PDMS, Teflon and octadecyltrichlorosilane monolayers on Sillicon surfaces) both in the presence and absence of an applied electric field in order to control the packing. It was observed that 3D well-ordered colloidal structures prefer hydrophobic surfaces while a hydrophilic surface gives rise to an amorphous structure with a relatively well-ordered 2D colloidalmonolayer at the periphery of the ring [8,9]. One possible reason for that is the presence of a close-packed population of relatively new phenomena of nanobubbles on the hydrophobic surface that affects the arrangement of the colloidal particles [10-12]. The nanobubbles are stabilized by small quantities of salt anions that are present in the water [13]. However different anions possess different propensity to water/air interface that is indicated by the Hofmeister series [14]. It is anticipated that this characteristic will affect the order of the nanobubbles on the surface and therefore the order of the colloidal particles allowing a crystal growth with various unit cells. The size of the nanobubbles is controlled by the concentration of anions adsorbed on the water/air interface [13]. Therefore one can expect that by varying salt concentration and consequently the size of the nanobubbles, their separation and even their arrangement will be altered. In this manner structures other than FCC can be produced, for example opal-like structure with low fill factor. The size and the packing of the nanobubbles will be monitored by AFM,Total Internal Reflection Fluorescence and Dynamic Light Scattering Technique. X-ray Diffraction will be used to determine the crystal structure formed by the colloidal particles. The charge present on the nanobubbles allows their manipulation with the electric field. Itcan be achieved by using small droplets of a solutioncontaining particles and different types of salts on hydrophobic surfaces to which an electric field is applied. In electrowetting experiments, droplets with different types of salts have shown distinct responses on electric field application [15], a behaviour that can be attributed to the different size and properties of nanobubbles on the hydrophobic surface. This behaviour of droplets can be used to order colloidal particles. These particles will have an induced dipole moment in an electric field so their alignment along the electric field can be correlated with nanobubbles due to a layer of anions and dipole moment interaction. It is therefore expected to affect the crystal structure that will be formed by colloidal particles acting as a template for crystal growth. Application of the electrowetting phenomena is proved to be efficient for the colloidal crystal growth from a solution of deionized water with polystyrene particles on Mica surfaces [16]. For experiments we will use standard electrowetting setup: droplet with the solution resting on coated hydrophobic surface with the ITO conductive layer; another electrode will be immersed in that droplet and then electric field will be applied. Application of the electric field will enhance evaporation of the liquid as well. We would like to use colloidal crystals, obtained by the above mentioned method, to investigate the influence of the photonic band gap, pseudo or complete, on the intensity of the Second Harmonic Generation (SHG). The formation mechanism of SHG signal is somewhat similar to that of fluorescence signal differing in the presence of a virtual energy state for the first and real energy state for the last. Recent experiments have demonstrated that the fluorescence signal of dye molecules embedded into a FCC colloidal crystal was suppressed due to photon confinement and the presence of photonic band gap [17]. Given the mechanism formation similarity, this gives rise to the question: what will happen to the intensity of SHG signal in the colloidal crystal? Unlike the real energy state, virtual energy state has no lifetime and therefore it cannot be delayed or suppressed. Will it therefore be enhanced? To answer these questions we will embed a solution of octupolar molecules (for example 1,3,5-tris[(4-nitrophenyl)ethynyl]-2,4,6-tris(octyloxy)benzene) that possess hyperpolarizability [18] and thus respond with a SHG signal when illuminated by light with a certain wavelength into colloidal crystal. Prepared in such a way, we will illuminate the sample with light of a specific wavelength and then analyze the SHG signal comparing it with a reference signal. The outcome of this study can be applied towards more efficient SHG microscopy and laser applications. In conclusion, the major goals of the project are: 1) to understand the physics the colloidal particle and water/polymer interface interaction that can be used as a unique method for controlling colloidal crystal packing and growth, combining the effects of confinement and the application of an electric field 2) to use these colloidal crystals to study the effect of photon confinement on the SHG signal intensity. [1] B. Comiskey, J. D. Albert, H. Yoshizawa and J. Jacobson, NATURE 1998, 394 (16), 253 [2] R. Biswas, M. M. Sigalas, G. Subramania, and K.-M. Ho, Phys. Rev. B, 1998, 57, 3701 [3] T. Solomon and M. J. Solomon, J. Chem. Phys., 2006,124, 134905. [4] J. Hilhorst, M. M. van Schooneveld, J. Wang, E. de Smit, T. Tyliszczak , J. Raabe , A. P. Hitchcock, M. Obst, F. M. F. de Groot, and A. V. Petukhov, Langmuir, 2012, 28, 3614. [5] E. C. M. Vermolen, A. Kuijk, L. C. Filion, M. Hermes, J. H. J. Thijssen, M. Dijkstra, and A. van Blaaderen PNAS , 2009, 106 (38), 16063 [6] V. N. Manoharan and D. J. Pine, MRS BULLETIN, 2004, 91 [7] L. González-Urbina, K. Baert, B. Kolaric, J. Pérez-Moreno and K. Clays, Chem. Rev., 2012, 112 (4), 2268. [8] H.-Y. Ko, J. Park, H. Shin, and J Moon, Chem. Mater., 2004, 16 (22), 4212 [9] D. M. Kuncicky, K. Bose, K. D. Costa, and O.D. Velev, Chem. Mater. 2007, 19, 141 [10] O.I. Vinogradova, N.F.Bunkin, N.V.Churaev, O.A. Kiseleva, A.V.Lobeyev and B.W.Ninham, Journal of Colloid and Interface Science, 1995, 173, 447 [11] A. C. Simonsen, P. L. Hansen, and B. Klösgen, Journal of Colloid and Interface Science 2004, 273, 291. [12] A. Poynor, L. Hong, I. K. Robinson, S. Granick, Z. Zhang and P. A. Fenter Phys Rev Lett., 2006,97, 266101. [13] E. Duval , S. Adichtchev, S. Sirotkin and A. Mermet, Phys Chem Chem Phys., 2012,14(12), 4125 . [14] D. J. Tobias and J. C. Hemminger, SCIENCE, 2008, 319, 1197. [15] O.Kruglova Unpublished results. [16] J. Kleinert, S. Kim, and O. D. Velev, Langmuir, 2010, 26(12), 10380 [17] B. Kolaric, K. Baert, Renaud A. L. Vallée, M. Van der Auweraer and K. Clays, Chemistry of Materials, 2007, 19(23), 5547. [18] S. V. Cleuvenbergen, G. Hennrich, P. Willot, G. Koeckelberghs, K. Clays, T. Verbiest, and M. van der Veen, Journal of Physical Chemistry C, 2012, 116(22), 12219." "Nanopore Transistors: Characterisation and Application Development" "Pol Van Dorpe" "Quantum Solid State Physics (QSP)" "A Field-Effect Transistor (FET) is incorporated in a Nanopore to allow for high-speed detection of biomolecule translocation. The Nanopore FET is sensitive to local potentials inside the pore and through its transconductance (transistor gain) converts these gating potentials into an easily measurable current. The performance of this device is characterized and the application of the device for protein identification is developed. The fundamental limitations on the sensitivity of sensing proteins with a Nanopore transistor are explored by combining simulation and experimental results." "Effects of radiation on state-of-the-art CMOS image sensors" "Guy Meynants" "Electronic Circuits and Systems (ECS)" "A lot of progress has been made on the understanding of radiation effects on CMOS image sensors (CIS). However, this is limited to pixels operating in a “rolling shutter” mode and with a classic 3-transistor or 4-transistor pixel topology. Meanwhile many new process steps were introduced in CIS technology which have effects on radiation tolerance (like backside illumination or deep trench isolation) and several new pixel architectures have been proposed, like global shutter pixels and pixels for Time-of-Flight (TOF) 3D imaging. Little is known yet on the radiation tolerance of devices using these latest technologies. This project aims to perform the first steps in radiation assessment of these latest generation of pixel architectures and CIS technologies, based upon standard devices. It hopes to trigger follow-on projects in the field of global shutter and time-of-flight imagers." "Radiation hardened high-speed digital circuits with multi-cell upset mitigation techniques for reliable communication links in nanoscale technologies" "Paul Leroux" "Electronic Circuits and Systems (ECS)" "In this research project, innovative circuit techniques will be developed to enable low power, extremely high-speed radiation hardened digital communication links. Such communication channels are required in complex nuclear facilities such as the Large Hadron Collider, nuclear fusion power plants and high-performance satellites. Generally, digital chips become faster each year with smaller transistors, but they also become more sensitive to high-energy particles coming from nuclear reactions, accelerated beams or cosmic radiation. In the past, such digital systems were protected with triple redundancy. However, due to the shrinking transistor sizes, this is becoming less effective and alternative protection strategies with advanced place methods are required. Radically new digital chip design techniques will be developed to ensure that such digital blocks can be made successfully redundant with advanced algorithms that check whether the geometrical location of millions of digital cells are adequate for surviving the harshest radiation environments. The approach that will be used is based on TCAD simulations (to simulate individual and groups of transistors) and charge sharing between various neighboring cells such that a digital radiationinduced soft-error rate model can be compiled for each multi-million transistor digital netlist. These methods and algorithms will allow to establish radiation hardened digital designs without sacrificing any performance. " "Advanced Electrical Characterization with Machine Learning: Extracting Device Information with Less Data" "Jesse Davis, Michel Houssa" "Declarative Languages and Artificial Intelligence (DTAI), Semiconductor Physics" "MetalOxide Semiconductor Field-Effect Transistors (MOSFETs) are an essential building block for all electronic systems today. The integration of a large number of tiny MOSFETs into a compact chip resulted in smaller, quicker, and less expensive circuits than discrete electronic components-based circuits. These transistors are composed of single gates on Silicon bulk or on insulators (SOI), tri-gates (FinFET), and gate-all-around called GAAFET, nanosheets, or nanoribbons. New materials like ultra-thin WS2 introduced into disruptive architectures are today in the research pipeline to enter into production by 2030-2040. To provide a few figures on the importance of the market of advanced MOSFETs, while in 2020, the Global Gate All Around FET technology Market share was $22.14 million, it is predicted to reach $472.25 million by 2030, with North America being the most significant market share in the Global GAAFET technology market and Asia being the main fabrication center of these advanced transistors. Integrated Circuits testing has contributed to a significant portion of nanoscale technologies' total manufacturing and cost. The reason behind among others is that silicon characterization and parameter extraction flow utilize a large area overhead due to the complexity of different test structures to cope with a surge of defects resulting from unprecedented complex fabrication flows for GAA devices for instance. To greatly reduce the time and cost required for measurement of the on-chip test, an early detection of the numerous sources of variability in advanced process technologies is a key challenge to ensure robust circuit performance as well as high manufacturing yield. Ultimately, there is an absolute need to reverse the current trend that it is impossible to proceed with current-voltage measurements for every on-chip monitoring device on a significant amount of dies in a wafer. In this work, we aim to search for the electrically active and non-electrically active defects created during the complicated fabrication steps of the advanced devices leveraging machine learning algorithms, and state-of-the-art physical characterization techniques combined with our expertise in physic-aware device modeling. Also, we would like to offer a new machine learning architecture that reproduces as accurately as possible Id-Vg outputs of the advanced transistors processed in our prototype R&D line. This will use their physical features and replicates the dimensions, materials, structures, underlying physics, and electrical characteristics. In this PhD, we plan first to further develop an existing software that provides an efficient classification (functional or not functional device) of the MOS field-effect transistors depending on the shape of their 4-terminal I-V output characteristics. To improve greatly its prediction accuracy, a literature search of state-of-the-art deep learning methods such as Yolov5, ResNet, EfficientNet, and DeciNet will be performed and additional modules will be plugged into the CNN-based AI software and tested. Data of functional devices from production line filtered by ML classifier will be collected. We will apply the most recently-developed data mining techniques to find not only a correlation between data but also common patterns. In the second part of the thesis, electrical characteristics of functional devices will be combined with the physical constraints to create a ML model for producing potential electrical characteristics data of the prototype devices. The goal will be to offer an early detection of the hard failure of the devices but also classified defects and/or defects patterns that may impact or not the output characteristics of the final advanced pre-production transistors. Finally, the learning on the electrically active defects associated with the new device integration schemes, new materials, or new process recipes will be ported to the design technology co-optimization (DTCO) level to help the designers to propose variability controlled SRAM circuit design for instance."