An Experimentally-Validated Verilog-A SPAD Model Extracted from TCAD Simulation

Single-photon avalanche diodes (SPAD) are photodetectors with exceptional characteristics. This paper proposes a new approach to model them in Verilog-A HDL with the help of a powerful tool: TCAD simulation. Besides, to the best of our knowledge, this is first model to incorporate a trap-assisted tunneling mechanism, a cross-section temperature dependence of the traps, and the self-heating effect. Comparison with experimental data establishes the validity of the model.Junta de Andalucía TIC 2012-2338Ministerio de Economía y Competitividad TEC2015-66878-C3-1-ROffice of Naval Research (USA) N00014141035

Microwave band on-chip coil technique for single electron spin resonance in a quantum dot

Microwave band on-chip microcoils are developed for the application to single electron spin resonance measurement with a single quantum dot. Basic properties such as characteristic impedance and electromagnetic field distribution are examined for various coil designs by means of experiment and simulation. The combined setup operates relevantly in the experiment at dilution temperature. The frequency responses of the return loss and Coulomb blockade current are examined. Capacitive coupling between a coil and a quantum dot causes photon assisted tunneling, whose signal can greatly overlap the electron spin resonance signal. To suppress the photon assisted tunneling effect, a technique for compensating for the microwave electric field is developed. Good performance of this technique is confirmed from measurement of Coulomb blockade oscillations.Comment: 7 pages, 8 figures, Accepted for publication in Rev. Sci. Instrum. The bibliography file is update

The 'gated-diode' configuration in MOSFET's, a sensitive tool for characterizing hot-carrier degradation

This paper describes a new measurement technique, the forward gated-diode current characterized at low drain voltages to be applied in MOSFET's for investigating hot-carrier stress-induced defects at high spatial resolution. The generation/recombination current in the drain-to-substrate diode as a function of gate voltage, combined with two-dimensional numerical simulation, provides a sensitive tool for detecting the spatial distribution and density of interface defects. In the case of strong accumulation, additional information is obtained from interband tunneling processes occurring via interface defects. The various mechanisms for generating interface defects and fixed charges at variable stress conditions are discussed, showing that information complementary to that available from other methods is obtaine

Development of High Efficiency III/V Photovoltaic Devices

Developments of photovoltaic (PV) devices are driven by increasing needs for economically competitive renewable energy conversion. To improve the efficiency of PV devices for outdoor applications, the concept of intermediate band solar cell (IBSC) has been proposed to boost the conversation efficiency to 63% under concentrated suns illumination, which requires two-step photon absorption (TSPA) dominates among other competing processes: carrier thermal escape, tunneling and recombination. To optimize the design of III-V QD-IBSCs, first, the effect of electric field on band structure and carrier dynamics and device performances were quantitative investigated via simulation and experiments. Second, to experimentally increase TSPA at room temperature, novel QD systems related QD-IBSCs were designed, fabricated and characterized. The InAs/Al0.3GaAs QD-IBSC shows high TSPA working temperature towards 110K, promising for a room temperature IBSC under concentrated sunlight. Alternative QD systems including GaSb/GaAs and type II InP/InGaP were also investigated via band structure simulations. Meanwhile, developments of PV devices under indoor low intensity light (0.1 µW/cm2-1 mW/cm2) illumination not only enable long lifetime radio-isotope based batteries, but also, more important for the daily life, have the potential to promote an emerging market of internet of things by efficiently powering wireless sensors. Single junction InGaP PV devices were optimized for low intensity light sources using via simulations and statistical control. To reduce the dark current and increase the absorption at longer wavelengths (\u3e550 nm), several parameters including doping and thickness were evaluated. The experimental results on the devices show higher conversion efficiencies than other commercial PVs under varied indoor light sources: 29% under 1µW/cm2 phosphor spectrum and over 30% efficiency under LEDs illumination. In addition, the work includes developments of InAs nanowires epi-growth for PV applications. Several marks for selective area growth were successfully made

Compact Models for Integrated Circuit Design

This modern treatise on compact models for circuit computer-aided design (CAD) presents industry standard models for bipolar-junction transistors (BJTs), metal-oxide-semiconductor (MOS) field-effect-transistors (FETs), FinFETs, and tunnel field-effect transistors (TFETs), along with statistical MOS models. Featuring exercise problems at the end of each chapter and extensive references at the end of the book, the text supplies fundamental and practical knowledge necessary for efficient integrated circuit (IC) design using nanoscale devices. It ensures even those unfamiliar with semiconductor physics gain a solid grasp of compact modeling concepts