Francisco Gamiz

Francisco Gamiz
University of Granada | UGR · Department of Electronics and Computer Technology

Ph.D.

About

388
Publications
34,962
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4,691
Citations
Additional affiliations
January 1992 - present
University of Granada
Position
  • Professor (Full)

Publications

Publications (388)
Article
We employ atomistic calculations to study charge distribution in few-layer MoS2 structures with an applied perpendicular electric field. The results suggest a simple continuum model consisting of alternating regions which represent the semiconductor layers and the Van der Waals gaps between them. Such model is a first step towards an accurate simul...
Article
In this work, the electrical performance of a novel reprogrammable FDSOI device with dual-doping at source/drain and only two top gates is investigated through advanced 3D TCAD simulations. The static and dynamic operations are evaluated and compared with those of traditional Schottky barrier RFETs and standard 28 nm FDSOI MOS transistors under rea...
Article
Full-text available
The electrical performance of Z2-FET and memory operations of matrix are demonstrated at high temperatures up to 125 ∘C. The sharp subthreshold slope is maintained and the reliable operation is ensured within the memory window of 229 mV even though the turn on voltage of ‘0’-and ‘1’-states are shifted to lower voltage. The ‘0’-state current remains...
Article
Full-text available
Two-dimensional materials, including molybdenum disulfide (MoS2), present promising sensing and detecting capabilities thanks to their extreme sensitivity to changes in the environment. Their reduced thickness also facilitates the electrostatic control of the channel and opens the door to flexible electronic applications. However, these materials s...
Article
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The implementation of a source to drain tunneling in ultrascaled devices using MS-EMC has traditionally led to overestimated current levels in the subthreshold regime. In order to correct this issue and enhance the capabilities of this type of simulator, we discuss in this paper two alternative and self-consistent solutions focusing on different pa...
Article
The structure of zero impact ionization, zero subthreshold swing field-effect transistor (Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -FET) has been modified by stacking a half side of back-gate (BG) with a heavily doped silicon layer instead of full covered BG. Through the modification,...
Chapter
Graphene and two-dimensional (2D) materials have experienced an outstanding development in the last few years. The confinement of the carriers and the improved electrostatic control in the thin channels of fabricated devices have demonstrated surprising results in terms of electrical, photonic, and mechanical properties. However, these properties a...
Article
Full-text available
Schottky junction reconfigurable FETs suffer from limited output currents to drive the following stages, jeopardizing their viability for high-end applications. This drawback becomes dramatic at low voltages. In this work, an analogous novel low-bias reprogrammable device is presented. It features a dual PN doping at source and drain which improves...
Chapter
This chapter presents a protocol to carry out the systematic characterization of random telegraph noise in MOSFETs assisted by low-frequency noise measurements. The usefulness of this method is demonstrated through its application for monitoring the distribution of traps over state-of-the-art transistors and the influence of static low magnetic fie...
Article
Full-text available
As complementary metal-oxide-semiconductor (CMOS) transistors approach the nanometer scale, it has become mandatory to incorporate suitable quantum formalism into electron transport simulators. In this work, we present the quantum enhancement of a 2D Multi-Subband Ensemble Monte Carlo (MS-EMC) simulator, which includes a novel module for the direct...
Chapter
As the scaling of electronic devices approaches to the end of the roadmap quantum phenomena play an important role not only in the electrostatics but also in the electron transport. This work presents the capabilities of a novel implementation of Multi-Subband Ensemble Monte Carlo simulators (MS-EMC) including transport quantum phenomena. In partic...
Chapter
Novel numerical techniques are needed in advanced simulation tools in order to accurately describe the behavior of nanoelectronic devices. In this work, two different numerical techniques for statistical enhancement are included in a 2D Multi-Subband Ensemble Monte Carlo (MS-EMC) simulator. First, the consideration of the Fermi-Dirac statistics for...
Article
This work experimentally demonstrates the memory operations of a Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -FET (Zero impact ionization, Zero subthreshold swing) matrix without the use of selectors. Selection and deselection of memory cells in the same bit line can be controlled by modu...
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In this article, we present a new method to mitigate the effect of the charge collected by trigate FinFET devices after an ionizing particle impact. The method is based on the creation of an internal structure that generates an electrical field that drives the charge generated by the ion track out of the sensitive device terminals. This electrical...
Article
Full-text available
Dynamic random access memory (DRAM) cells are commonly used in electronic devices and are formed from a single transistor and capacitor. Alternative approaches, which are based on the floating body effect, have been proposed that could reduce manufacturing complexity and minimize the cell footprint by removing the external capacitor. Such capacitor...
Article
3-D numerical technology computer-aided design simulations, based on experimental results, are performed to study the origin of the large Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -FET dynamic random access memory (DRAM) memory cell-to-cell variability on fully depleted silicon-on-insul...
Article
The experimental time-dependent dielectric breakdown and ON voltage reliability of advanced FD-SOI Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -FET memory cells are characterized for the first time. The front-gate stress time is shown to significantly modulate the ON voltage and, hence, t...
Article
The electrical characteristics of band modulation FET are investigated with energy band diagrams between drain to source through intrinsic gate region according to front/back gates and drain bias conditions. The drain current-voltage and transfer characteristics show extremely steep slope with minimum subthreshold swing of 1.6 mV/decade. Memory win...
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Full-text available
A Near-Field Scanning Microwave Microscope (NSMM) for the characterization of semiconductor structures has been designed, simulated and fabricated. The present NSMM system is based on a home-made coaxial-cavity resonator which is fed by a Keysight N5242A PNA-X Network Analyzer. The inner conductor of the coaxial resonator is connected to a sharpene...
Article
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This paper addresses the low-frequency noise characterization of Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -FET structures. These double-gated p-i-n diode devices have been fabricated at STMicroelectronics in an ultrathin body and box (UTBB) 28-nm FDSOI technology and designed to operat...
Article
We thoroughly compare the DC electrical behavior of n-MOS transistors based on Si nanowires with 〈100〉 and 〈110〉 channel orientations by means of Multi-Subband Ensemble Monte Carlo simulations. We find that the drain current depends on the nanowire diameter and it is slightly, but consistently, larger for 〈100〉 than for 〈110〉 nanowires. The observe...
Article
Thin-oxide Z ² -FET cells operating as capacitor-less DRAM devices are experimentally demonstrated. Both the retention time and memory window demonstrate the feasibility of implementing this cell in advanced 28 nm node FDSOI technology. Nevertheless a performance drop and higher variability with respect to thicker oxide Z ² -FET cells are observed.
Article
A recently reported zero impact ionization and zero subthreshold swing device Z2FET is a promising candidate for capacitor-less dynamic random access memory (DRAM) memory cell. In the memory operation, data retention time determines refresh frequency and is one of the most important memory merits. In this paper, we have systematically investigated...
Article
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With the upcoming Internet of Things (IoT), low-power devices are becoming mainstream these days. The need for memory elements able to operate at reduced biasing conditions is therefore of utmost importance. In this paper, one of the most promising capacitor-less dynamic RAM cell, the Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlin...
Conference Paper
As device dimensions are scaled down, the use of strained channels as performance booster becomes of special relevance. Moreover, the inclusion of quantum effects in the transport direction is imperative to predict the performance of future transistors. In particular, Source-to-Drain tunneling (S/D tunneling) is presented as a scaling limit in sub-...
Article
The inclusion of quantum effects in the transport direction plays an important role in the extensive research of ultrascaled electronic devices. In this context, it is necessary to study how these phenomena affect different technological architectures in order to conclude which one can be the best candidate to replace standard technology. This pape...
Article
Among the different types of bilayer tunneling field-effect transistors exploiting interband tunneling phenomena with tunneling directions aligned with gate-induced electric fields, the utilization of InAs/GaSb channels proves to be an appealing means to enhance ON-current levels. Ultrathin channel thicknesses make quantum confinement be the agent...
Article
Graphene is considered to be a promising material for the development of the next generation of asphalt binders to be used in road engineering. Nonetheless, in spite of the potential advantages that graphene could add to bitumen, there are currently very few studies able to quantify its real contribution to the performance of existing binders. This...
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Full-text available
2D numerical TCAD simulations are used to infer the behavior of III-V capacitor-less DRAM cells. In particular, indium gallium arsenide on insulator technology (InGaAs-OI) is selected to verify the viability of III-V MSDRAM (Meta-Stable-Dip RAM) cells. The cell performance dependence on several parameters (such as the back-gate voltage, semiconduct...
Article
Random Telegraph Noise has been experimentally characterized in two sets of nMOSFET devices under the influence of perpendicular magnetic fields at room temperature. The experimental measurements were performed following a systematic trapping phenomena characterization protocol. The results reveal that the drain-source current exhibits an unexpecte...
Article
Electron–Hole Bilayer Tunneling Field-Effect Transistors are typically based on band-to-band tunneling processes between two layers of opposite charge carriers where tunneling directions and gate-induced electric fields are mostly aligned (so-called line tunneling). However, the presence of intense electric fields associated with the band bending r...
Article
In this letter, a functional Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -FET DRAM memory matrix is experimentally demonstrated for the first time. Word-level operation with simultaneous reading and programming accesses is successfully proved. Disturbance is also explored, and the results...
Conference Paper
Advanced 28 nm node FDSOI Z2-FETs with thin top-gate insulator are characterized as capacitor-less DRAM cells. Results demonstrate effective Z2-FET memory behavior for narrow devices (below 1 μm). As compared with thicker gate oxide Z2-FETs, thinning the insulator yields lower performance in terms of retention, variability and stability of the logi...
Conference Paper
Full-text available
In this work, we have designed, simulated and fabricated a near-field scanning microwave microscope based on a coaxial cavity resonator. The coaxial cavity resonator is fed by a Keysight N5242A PNA-X Network Analyzer. The inner conductor of the coaxial resonator is connected to a sharpened tungsten tip home-made in our Lab following an electrochemi...
Article
We developed a Multi-Subband Ensemble Monte Carlo simulator for non-planar devices, taking into account two-dimensional quantum confinement. It couples self-consistently the solution of the 3D Poisson equation, the 2D Schrödinger equation, and the 1D Boltzmann transport equation with the Ensemble Monte Carlo method. This simulator was employed to s...
Article
Within the research in bilayer tunneling field-effect transistors (TFETs) exploiting interband tunneling phenomena with tunneling directions aligned with gate-induced electric fields, simulation results for the heterogate electron-hole bilayer TFET (HG-EHBTFET) showed that this type of devices succeeded in suppressing the parasitic tunneling leakag...
Article
The band-modulation and sharp-switching mechanisms in Z²-FET device operated as a capacitorless 1T-DRAM memory are reviewed. The main parameters that govern the memory performance are discussed based on detailed experiments and simulations. This 1T-DRAM memory does not suffer from super-coupling effect and can be integrated in sub-10 nm thick SOI f...
Article
Full-text available
2-D numerical simulations are used to demonstrate the Z²-FET as a competitive embedded capacitor-less dynamic random access memory cell for low-power applications. Experimental results in 28-nm fully depleted-silicon on insulator technology are used to validate the simulations prior to downscaling tests. Default scaling, without any structure optim...
Article
Thin and ultrathin body-contacted Silicon-on-Insulator MOS-transistors have been used for the direct experimental measurement of the stationary body potential and impact ionization current generated at moderate and high electric field regimes. The large influence of the channel length on the evolution of the body potential as well as the severe los...
Article
The Z <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -FET operation as capacitorless DRAM is analyzed using advanced 2-D TCAD simulations for IoT applications. The simulated architecture is built based on actual 28-nm fully depleted silicon-on-insulator devices. It is found that the triggering...
Conference Paper
Full-text available
Traditional memory devices are facing more challenges due to continuous down-scaling. 6T-SRAM suffers from variability and reliability issues, which introduce cell stability problems. DRAM cells with one transistor, one capacitor (1T1C) struggle to maintain refresh time. Efforts have been made to find new memory solutions, such as one transistor (1...
Conference Paper
Full-text available
In this work, we have developed a near-field scanning microwave microscopy method and applied it to study semiconductor samples. To do so, we have used a commercial Atomic Force Microscope (NT-NMDT Integra) to which we have coupled a half wavelength micro-strip line resonator and an Agilent N5242A PNA-X Network Analyzer. The AFM tip is connected at...
Article
A systematic study of a capacitorless 1T-DRAM fabricated in 28 nm FDSOI technology is presented. The operation mechanism is based on band modulation. The Z²-FET memory cell features a large current sense margin and small OFF-state current at 25 °C and 85 °C. Moreover, low power consumption during state ‘1’ writing is achieved with ~ 0.5 V programmi...
Article
Full-text available
The electrostatic performance of p-type nanowires (NWs) made of InSb and GaSb, with special focus on their gate capacitance behavior, is analyzed and compared to that achieved by traditional semiconductors usually employed for p-MOS such as Si and Ge. To do so, a self-consistent kp simulator has been implemented to achieve an accurate description o...