The Medipix4 chip is the latest member in the Medipix/Timepix family of hybrid pixel detector chips aimed at high-rate spectroscopic X-ray imaging using high-Z materials. It can be tiled on all 4 sides making it ideal for constructing large-area detectors with minimal dead area. The chip is designed to read out a sensor of 320 x 320 pixels with dimensions of 75 {\mu}m x 75 {\mu}m or 160 x 160 pixels with dimensions of 150 {\mu}m x 150 {\mu}m. The readout architecture features energy binning of the single photons, which includes charge sharing correction for hits with energy spread over adjacent pixels. This paper presents the specifications, architecture, and circuit implementation of the chip, along with the first electrical measurements.

In this paper an analytical non-quasi-static (NQS) model for long-channel symmetric double-gate junctionless field-effect transistors (JLFETs) operating in depletion mode is proposed for the first time. The model addresses the limitations of existing DC and AC models by incorporating time-dependent current continuity equations which are essentials to predict JLFETs behavior at high frequencies. Leveraging charge-based equations, the NQS model captures the delay between current and applied potentials arising beyond the quasi-static regime. Analytical solutions for small-signal perturbations allow the calculation of key transistor small signal parameters such as the gate transadmittance. The model’s validity is tested against TCAD simulations for various device parameters, including doping concentration and channel thickness. Good agreement between the model and TCAD simulations is observed across a wide frequency range, up to highly non-static transport conditions. This work lays the foundation for a comprehensive RF model of JLFETs for high-frequency applications.

The semiconductor industry continues to grow and innovate; however, companies are facing challenges in growing their workforce with skilled technicians and engineers. To meet the demand for well-trained workers worldwide, innovative ways to attract skilled talent and strengthen the local semiconductor workforce ecosystem are of utmost importance. FOSS CAD/EDA tools combined with free and open-access PDKs can serve as a new platform for bringing together IC design newbies, enthusiasts, and experienced mentors.

The 28 nm CMOS technology was selected as a promising candidate to upgrade electronics of particle detectors at CERN. Despite the robustness of this node to ultra-high levels of total ionizing dose has been proven, the resilience to 10161MeVneq/cm2 fluences is still unknown. Displacement damage effects on two 28 nm CMOS technology processes were therefore investigated through proton and neutron irradiation up to the fluences of interest for high energy physics applications. N-type and p-type core and I/O transistors with different sizes were studied. The results of the extensive irradiation campaign revealed that the 28 nm CMOS node was indeed affected by either proton or neutron. However, through X-ray irradiation it was possible to evidence that the observed radiation-induced degradation was caused by the amount of total ionizing dose deposited during neutron and proton exposure, rather than by displacement damage. These results support that 28 nm CMOS technology is suitable for applications in CERN particle detectors.

The radiation response of MOS transistors in a 22 nm Fully Depleted Silicon-On-Insulator (FDSOI) technology exposed to ultra-high total ionizing dose (TID) was investigated. Custom structures including n- and p-channel devices with different sizes and threshold voltage flavours were irradiated with X-rays up to a TID of 100 Mrad(SiO 2 ) with different back-gate bias configurations, from -8 V to 2 V. The investigation revealed that the performance is significantly affected by TID, with the radiation response being dominated by the charge trapped in the buried oxide.

This paper introduces a simplified and design-oriented version of the EPFL HEMT model [1], focusing on the normalized transconductance-to-current characteristic ($G m / I_{D}$). Relying on these figures, insights into GaN HEMT modeling in relation to technology offers a comprehensive understanding of the device behavior. Validation is achieved through measured transfer characteristics of GaN HEMTs fabricated at IMEC on a broad range of biases. This simplified approach should enable a simple and effective circuit design methodology with AlGaN/GaN HEMT heterostructures.

The radiation response of MOS transistors in a 22 nm Fully Depleted Silicon -On -Insulator (FDSOI) technology exposed to ultra -high total ionizing dose (TID) was investigated. Custom structures including n- and p -channel devices with different sizes and threshold voltage flavours were irradiated with X-rays up to a TID of 100 Mrad(SiO2) with different back -gate bias configurations, from -8 V to 2 V. The investigation revealed that the performance is significantly affected by TID, with the radiation response being dominated by the charge trapped in the buried oxide.

The 28 nm CMOS technology was selected as a promising candidate for upgrade of the electronics of particle detectors at CERN. Despite the robustness of this node to ultrahigh levels of total ionizing dose has been proven, the capability to withstand 10 16 1 MeV neq/cm 2 fluences is still unknown. Displacement damage effects on two 28 nm CMOS technology processes were therefore investigated through proton and neutron irradiation up to the fluences of interest for high energy physics applications. N-type and p-type core and I/O transistors with different sizes were studied. The results of the extensive irradiation campaign revealed that the 28 nm CMOS node was indeed affected by either proton or neutron. However, through X-ray irradiation was possible to determine that the observed radiation-induced degradation was caused by the amount of total ionizing dose deposited during neutron and proton exposure rather than displacement damage. These results prove that 28 nm CMOS technology is suitable for applications in CERN’s particle detectors.

The design, fabrication and testing of a low-cost portable medical device for the detection and quantification of exosomes is presented in this paper. The portable medical device comprises a sensor array that can detect the presence of exosomes and quantify its concentration, a micro fluidic device that handles the human serum containing the exosomes, and all the necessary readout and control electronics. Measurement results performed with exosomes showed that the portable medical device can detect exosomes with a concentration of $2.5\mathrm{x}10^{8}/\mu \mathrm{L}$ thus paving the way to a wide range of diagnostic applications.

The discovery of a large fab-to-fab variability in the TID response of the CMOS technologies used in the design of ASICs for the particle detectors of the HL-LHC triggered a monitoring effort to verify the consistency of the CMOS production process over time. As of 2014, 22 chips from 3 different fabs in 130 nm CMOS technology and 11 chips from 2 different fabs in 65 nm CMOS technology have been irradiated to ultra-high doses, ranging from 100 Mrad(SiO2) to 1 Grad(SiO2). This unprecedented monitoring effort revealed significant fab-to-fab and run-to-run variability, both dependent on the characteristics of the MOS transistors.

Solid-state qubits can be implemented with electrostatically confined quantum dots in semiconductors, allowing gate voltages to independently control the electrochemical potentials of each quantum dot. Quantum dots offer high levels of reliability and scalability. In this paper, along with our proposed approach based on the Generalized Hubbard model followed by Fermi's Golden rule, the charge stability diagram of a double quantum dots system with two electrons has been studied extensively. The validity of the presented approach is confirmed by experimental data. Using Fermi's Golden rule for mapping the charge stability diagram, we have deeply studied the temperature effects arising from both the Hamiltonian and transport. In addition, spin-exchange, pair-hopping, and the occupation-modulated hopping parameters on the states of the charge stability diagram are deeply discussed. Furthermore, we incorporate the Zeeman energies in the Hubbard model in order to theoretically study the spin splitting caused by an external magnetic field applied to the quantum dots. In particular, the aim of this paper is to rely on fundamental physical concepts in order to model and optimize the singlet–triplet qubit in quantum dots. In this study, the probabilities associated with singlet and triplet states have been modeled and analyzed under the impacts of intrinsic and extrinsic parameters. This will help us to find the optimal condition for coupling between double dots and provides us the design rules in terms of physical parameters to efficiently design, measure and sense, initialize, manipulate, and readout of the qubit state.

Predicting the performance of solar cells though analytical models is important for the theory-guided optimization of these devices. Earlier models neglect the impact of the optical generation in the quasi-neutral regions of a perovskite solar cell. Here, a new model is developed that takes optical generation in these regions into account. The model includes the full depletion approximation and the drift-diffusion transport mechanisms. A comparison with earlier models demonstrates the improved predictive power of the developed model. In addition, the accuracy of the model was assessed by comparing it prediction to experimental data obtained from working devices.

This paper deals with a new analytical model for microfluidic passive mixers. Two common approaches already exist for such a purpose. On the one hand, the resolution of the advection-diffusion-reaction equation (ADRE) is the first one and the closest to physics. However, ADRE is a partial differential equation that requires finite element simulations. On the other hand, analytical models based on the analogy between microfluidics and electronics have already been established. However, they rely on the assumption of homogeneous fluids, which means that the mixer is supposed to be long enough to obtain a perfect mixture at the output. In this paper, we derive an analytical model from the ADRE under several assumptions. Then we integrate these equations within the electronic-equivalent models. The resulting models computed the relationship between pressure and flow rate in the microfluidic circuit but also takes the concentration gradients that can appear in the direction perpendicular to the channel into account. The model is compared with the finite element simulation performed with COMSOL Multiphysics in several study cases. We estimate that the global error introduced by our model compared to the finite element simulation is less than 5% in every use case. In counterparts, the cost in terms of computational resources is drastically reduced. The analytical model can be implemented in a large range of modelling and simulation languages, including SPICE and hardware description language such as Verilog-AMS. This feature is very interesting in the context of the in silico prototyping of large-scale microfluidic devices or multi-physics devices involving microfluidic circuits, e.g. lab-on-chips.

Relying on the previously developed charge-based approaches, this paper presents a physics-based design space of negative capacitance in double-gate and bulk MOSFET architectures. The impact of thickness variation of the ferroelectric on the DC characteristics has been deeply investigated. The model precisely estimates a critical thickness of ferroelectric at instability conditions before the device goes into the hysteresis regime. Explicit relationships have been driven for hysteresis voltages which can be used as a general guideline for technology optimization of negative capacitance FETs.

Electrostatically confined quantum dots in semiconductors hold the promise to achieve high scalability and reliability levels for practical implementation of solid-state qubits where the electrochemical potentials of each quantum dot can be independently controlled by the gate voltages.In this paper, the current and charge stability diagram of two-well potentials arising from electrostatically defined double quantum dot (DQD) are analytically realized. We propose to apply the Generalized Hubbard model to find the Hamiltonian of the system. The proposed analysis takes the tunnel coupling between the dots, Coulomb interaction, and Zeeman energy arising from an external magnetic field into account. Using quantum master equations to predict the probability of the final states in a DQD system, we study the tunneling current through two quantum dots coupled in series with two conducting leads, and therefore, the charge stability diagram is theoretically investigated. The impact of the tunnel coupling and Zeeman energy on the charge stability diagram is deeply discussed. The validity of the presented analysis is confirmed by experimental data as well as the classical capacitance model.

This article analyzes the design space stability of negative capacitance double-gate junctionless field-effect transistors (NCDG JLFETs). Using analytical expressions derived from a charge-based model, we predict instability condition, hysteresis voltage, and critical thickness of the ferroelectric layers giving rise to the negative capacitance behavior. The impact of the technological parameters is investigated in order to ensure the hysteresis-free operation. Finally, the stability of NCDG JLFET is predicted over a wide range of temperatures from 77 to 400 K. This approach has been assessed with numerical TCAD simulations.

Recent advances in CMOS scaling have made circuits more and more sensitive to errors and dysfunction caused by ionizing radiation, even at ground level, requiring accurate modeling of such effects. Besides generation, transport, and collection of radiation-induced excess carriers, another phenomenon, called funneling, has to be modeled for an accurate prediction of soft errors. The funneling effect occurs when the radiation track crosses a space charge region and generates excess carriers with a density higher than the doping close to it. These carriers distort the electric field of the space charge region, deeply changing the transport mechanism, from diffusion in a field-free semiconductor to drift. The objective of this work is to include funneling as part of the generalized lumped devices model in order to obtain a complete tool for SPICE-compatible simulations of single-event effects (SEEs). The latter approach has been recently proposed to simulate radiation-induced charges in the silicon substrate and is based on the so-called generalized lumped devices that simulate charge generation, propagation, and collection using standard circuit simulators. The generalized devices are here extended to include funneling and used to simulate an alpha particle impinging on the bulk of nMOS and pMOS transistors. The results obtained are validated with TCAD numerical simulations. Finally, an static random-access memory (SRAM) struck by an alpha particle is analyzed. The model predicts that the occurrence of a soft error, i.e., flipping of memory state, may depend on whether or not there is funneling. This justifies the need for accurate modeling of funneling phenomena to predict SEEs in ICs.

We revisit some charge - voltage dependences for different architectures of field effect transistor, emphasizing on compactness and simplicity while maintaining a close link with physics, which makes these models predictive and accurate for general purposes of compact modeling.

The operation principle of a semiconductor nanowire (NW) ion-sensitive field-effect transistor (ISFET), denoted for pH sensing, is studied within the framework of this work. The physical processes in the system are mathematically modelled and presented in details. The dependences of the NW ISFET current-pH characteristics on NW geometrical and physical parameters are analyzed. The plots of the ISFET sensitivity versus pH at different NW radii, the thicknesses of the oxide layer, and the NW doping densities are presented. The obtained results are in qualitative agreement with the experimental data.

In this work, we present a simple compact model for junctionless ion-sensitive FETs (JL ISFET) operating in depletion. The sensitivity dependence on nanowire physical and geometrical parameters are discussed as guidelines for the device optimization. The model validation with COMSOL Multiphysics simulations is presented.