Papers by Keyword: Tunneling

Abstract: This paper investigates the dynamic conduction behavior of silicon carbide (SiC) MOSFETs in thesub-threshold regime. We demonstrate that controlled gate bias preconditioning, combined with timeresolvedelectrical measurements in thermal equilibrium, reveals a notable drift in the source-drainvoltage Vsd. The direction of this drift depends on the polarity of gate preconditioning and is directlyrelated to variations in the channel conduction. These effects are shown to be attributed to chargerelease from deep oxide traps, leading to a gradual shift in the flat-band voltage (Vfb) over time.Experimental results reveal that these dynamic effects are most prominent in the depletion and weakinversion regimes. Our findings highlight the influence of oxide trap dynamics on the body diodeforward voltage (Vf) and its significance for the reliability of SiC devices, specifically in its role asthe temperature-sensitive parameter.

Abstract: The paper investigates the tunneling currents through the gate terminals of the last MOSFET production and proposes a related structure, noted as p-NOI (planar-Nothing On Insulator) device. In fact, the p-NOI structure can arise as parasitic device in any MOSFET having a gate insulator sub-10nm thickness or can be separately produced to offer a tunneling device. The work principle of a p-NOI structure consists in the Fowler-Nordheim's tunneling of a thin insulator. Its architecture is derived from the Nothing On Insulator (NOI) device, using oxide instead vacuum. Essentially, the p-NOI current follows a metal-insulator-semiconductor trajectory. A critical issue is the field effect of a transistor that must be fulfilled by independent p-NOI device. In this purpose, a diffusion process seems to be the key. A planar p-NOI device with top three terminals is proposed. A diffusion process along to the Si-surface is a key technological step that offers distinct current traces.

Abstract: This paper starts from the leakage currents through the gates of the last MOSFET generations and propose a related structure, which can be inherently included as parasitic device in any future MOSFET sub-22nm or can be deliberated fabricated to induce its own behavior. This structure is abbreviated in this paper by p-NOI (planar-Nothing On Insulator) and it can be simply produced by the planar Si-technology. Its concept is derived from the NOI (Nothing On Insulator) concept, but replaces the vacuum with oxide. The conduction mechanism is based on a thin oxide tunneling, under the Fowler-Nordheim's law. The current flow occurs from a source to a lateral drain, without an inversion channel and without a lateral pn junction, as in the MOSFET case. A similar investigated device by other authors is a fabricated MIM (Metal-Insulator-Metal) structure, which is compared with the actual p-NOI simulation. Finally, a dual gate p-NOI device is investigated. The depletion-accumulation transition is captured by the static I-V static characteristics. Using two steps of oxide, of 2nm and 10nm, a second planar-NOI structure with three terminals was studied. The (G) terminal is associated to a Gate and the (S) terminal is associated to a Source of a Field Effect Transistor. Some particular applications as diode or transistor are emphasized versus the gate biasing regime.

Abstract: Temperature-dependent mechanisms and characteristics of 4H-SiC JBS rectifiers were described by theoretical and experimental results. The forward on-resistance of 4H-SiC JBS rectifier consists of several components, the drift region resistance is most sensitive to temperature than others. Comparing theoretical results with experimental data indicates that the leakage current is mainly affected by the thermionic emission, the image force barrier height lowering and tunneling. At different temperatures and reverse bias, the contribution of barrier lowering and the tunneling to leakage current is not the same. The temperature of critical point decreases with the increasing of the concentration of N_D or the reverse bias voltage V_R. Samples with the doping concentration of N_D=6.5E15cm^-3 and N_D=1E16cm^-3 were manufactured in the same process. The forward I–V-T and reverse I–V-T characteristics of the JBS samples were measured at different temperatures (300K to 523K), and temperature-dependent ideality factor, barrier height and resistance were also analyzed, which are in good agreement with simulation results.

Abstract: The special geological conditions of talus are often encountered in southwest China, it brings a lot of difficulties to tunnel construction. The formation mechanism and developmental properties of talus are analyzed in this paper. Based on field investigation on talus diseases, the hazard to tunnel engineering induced by talus and its corresponding measures are also analyzed. The results can be used for the safe and fast construction of tunnels which go through talus deposit.

Abstract: A design scheme based on IPSec VPN Service in VMware simulation platform was proposed. At first, this paper introduces the virtual machine and the working principle of IPSec VPN. Using VMware to construct a network simulation platform. Next,Through Routing and Remote Access Service、VPN Service of Windows Server 2008′s, the route between subnets was implemented. At last, the simulation experimental results show that the design of stable operation, high safety, no need of special routing equipment, and has low cost, easy to implement, is a safe, cheap, high performance design solutions.

Abstract: The reason situ stress is very complicated, and it is still not very clear question. In this paper, the construction process through practical engineering analysis on a variety of construction methods and steps arch tunnel to study the effects of different excavation methods and deep anchor support large section tunnel under guard by theoretical analysis of surrounding rock stress field, strain field and variation of the displacement field, analysis of different rock excavation methods, supporting stress state characteristics, in order to optimize the choice of tunneling method provides a theoretical basis. Under the conditions all kinds of rock reasonable steps to secure construction methods put forward and lay the foundation for long-term safety arch tunnel.

Abstract: As IPv4 address resource being exhausted, the transition from IPv4 to IPv6 is urgent. According to the status of the enterprise network, IPv6 forwarding performance and IPv6 transition technology of the enterprise network equipment was tested. Furthermore, IPv6 transition principles and process for the enterprise network were presented on this basis. In the transition program the cost, complexity, technology maturity and transition smoothness was taken into account. Test results and IPv6 transition program provide a reference for other enterprise network transition process.

Abstract: Isogeometric finite element methods and more recently boundary element methods have been successfully applied to problems in mechanical engineering and have led to an increased accuracy and a reduction in simulation effort. Isogeometric boundary element methods have great potential for the simulation of problems in geomechanics, especially tunneling because an infinite domain can be considered without truncation. In this paper we discuss the implementation of the method in the research software BEFE++. Based on an example of a spherical excavation we show that a significant reduction in the number of parameters for describing the excavation boundary as well as an improved quality of the results can be obtained.

Abstract: Drain current in an armchair graphene nanoribbon field effect transistor (AGNRFET) has been quantum mechanically modeled. The transfer matrix method (TMM) was employed to obtain the electron transmittance, and the obtained transmittance was then utilized to calculate the drain current by using the Landauer formula. The calculated results showed that the drain current increases with the gate and drain voltages. It was also shown that the threshold voltage for the device is around 0.3 V. In addition, the AGNR width influences the drain current of AGNRFET.