Search

The transient thermal crosstalk between the field-effect transistors (FETs) implemented on a silicon-on-insulator (SOI) substrate is examined. Findings reveal the achievement of a temperature resolution of ~50 mK, a time resolution of 5 ns and a temperature sensitivity of ~0.6 A/K.

This paper describes a technique for modeling single-event upsets due to ionizing radiation in a partially depleted silicon-on-insulator (SOI) MOSFET device. Two current pulses are used, one connected between the drain and body of the device, and the other connected between the body and source of the device. The physical representation of these two current sources is described in detail. Circuit modeling is verified against drift-diffusion field solver modeling and hardware experiments. The effects of manufacturing variation and operating condition variation on the qCrit of circuit storage elements are explored. Index Terms--Alpha particle, modeling, radiation event, single-event upset, soft error.

The study stated that a general approach, the EQ approach, to assess the scaling potential of nanoscale Si FETs based on both gate control (electrostatics) and quantum confinement. The report stated that with this EQ approach, the cylindrical wire FET and the planar double-gate MOSFET have approximately equal scaling capability, while the nonplanar wire structures are significantly better where the effective mass in the confinement direction of the planar MOSFET is relatively small.

Many in the microelectronics field view tunneling field-effect transistors (TFETs) as society's best hope for achieving a >10× power reduction for electronic devices; however, despite a decade of considerable worldwide research, experimental TFET results have significantly underperformed simulations and conventional MOSFETs. To explain the discrepancy between TFET experiments and simulations, we investigate the parasitic leakage current due to Auger generation, an intrinsic mechanism that cannot be mitigated with improved material quality or better device processing. We expose the intrinsic link between the Auger and band-to-band tunneling rates, highlighting the difficulty of increasing one without the other. From this link, we show that Auger generation imposes a fundamental limit on ultimate TFET performance. [ABSTRACT FROM AUTHOR]

Band-to-band tunneling was studied in ion-implanted P/N junction diodes with profiles representative of present and future silicon complementary metal-oxide-silicon (CMOS) field effect transistors. Measurements were done over a wide range of temperatures and implant parameters. Profile parameters were derived from analysis of capacitance versus voltage characteristics, and compared to secondary-ion mass spectroscopy analysis. When the tunneling current was plotted against the effective tunneling distance (tunneling distance corrected for band curvature) a quasi-universal exponential reduction of tunneling current versus, tunneling distance was found with an attenuation length of 0.38 nm, corresponding to a tunneling effective mass of 0.29 times the free electron mass (m 0), and an extrapolated tunneling current at zero tunnel distance of 5.3× 10 7 A/cm² at 300 K. These results are directly applicable for predicting drain to substrate currents in CMOS transistors on bulk silicon, and body currents in CMOS transistors in silicon-on-insulator. [ABSTRACT FROM AUTHOR]

Transistor amplification properties of a three-leg spirofluorene-based molecule are investigated, and the transistor is shown to possess usable current, voltage, and power gain. Current gain is facilitated since the source-drain legs are conjugated, whereas the gate (control) leg is unconjugated and spatially orthogonal, and voltage gain is enhanced by the efficient quantum-mechanical coupling to the gate. Full quantum-mechanical calculations were done for all three electrodes, using the density functional formalism and a plane-wave decomposition of the wave functions. [ABSTRACT FROM PUBLISHER]

It has recently been suggested that ferroelectric (FE) negative capacitance effects can be used to achieve steep subthreshold slope field-effect transistors, which are greatly desired for reducing energy consumption in modern digital electronics. Here, we propose that this concept can be improved by the introduction of a very thin metal or metal-like layer (a quantum metal) between the FE and the semiconductor channel. We show how to design this layer so that it attenuates the polarization charge of the FE, applying an appropriate charge to the semiconductor, while at the same time presenting a relatively constant capacitance to the FE layer, as is needed to stabilize the negative capacitance regime. For homogeneous polarization, we estimate that this device (a QMFeFET) can have extremely steep subthreshold characteristics (2 mV/decade over 11 decades) and that its energy and delay performance are advantageous. [ABSTRACT FROM AUTHOR]

The electrical characteristics of a heterojunction tunneling field-effect transistor (HETT), with a p-type \Si0.75\Ge0.25 source, have been measured as a function of strain. HETTs with channel transport and applied strain both in the [110] direction show a smooth monotonic change in drain current over a range of 0.09% compressive to 0.13% tensile strain. A measure \gamma = (d/d\ln JD)(d\ln JD/ds)\verts = 0 of the effect of strain s on tunneling current JD is proposed, which captures the dependence of the tunneling exponential argument on strain. An experimental value of \gamma = - \11.7 is extracted for the tensile case and compared to simulation results. We found theoretically that the value and sign of \gamma depend sensitively on the built-in strain at the Si–SiGe interface. [ABSTRACT FROM AUTHOR]

A distributed contact model is presented for a 1-D quasi-ballistic conductor deriving a contact resistance versus contact length as a hyperbolic cotangent relationship in terms of the quantum of resistance, the coupling conductance gc of the contact, and the ballistic mean free path (\lambdab). The model gave excellent fits to recent contact resistance-versus-contact length data for carbon nanotubes giving gc = \2 \ \mu\S/nm and \lambdab = \380 \ \nm. [ABSTRACT FROM PUBLISHER]

A simple potential mapping is used to show that tunneling through a single barrier, as in Schottky-barrier tunneling or source-to-drain tunneling in MOSFETs, cannot give rise to subthreshold swings below the thermionic limit (60 mV/decade at room temperature). While cognizant of the difficulty of proving a negative, it is thus highly unlikely that Schottky-barrier tunneling alone can result in reported instances of subthreshold swings that are less than 60 mV/decade. [ABSTRACT FROM AUTHOR]

Reduction of specific contact resistivity is one of the key items for downscaling of device feature size. This paper discusses an accurate method of measuring specific contact resistivity by using our simple four-point probe test structure having a small area, the interface resistance of which is to be measured, fabricated on a substrate that has low sheet resistance. We also show its application for direct specific contact resistivity measurements of several systems that have dopant dependence, i.e., the NiPtSi/Si, NiPtSi/SiGe, and Pt silicide systems, as well as the metal-metal system between silicide and contact plug metal. [ABSTRACT FROM AUTHOR]

We present the first realization of a monolithically integrated piezoelectronic transistor (PET), a new transduction-based computer switch which could potentially operate conventional computer logic at 1/50 the power requirements of current Si-based transistors (Chen 2014 Proc. IEEE ICICDT pp 1-4; Mamaluy et al 2014 Proc. IWCE pp 1-2). In PET operation, an input gate voltage expands a piezoelectric element (PE), transducing the input into a pressure pulse which compresses a piezoresistive element (PR). The PR resistance goes down, transducing the signal back to voltage and turning the switch 'on'. This transduction physics, in principle, allows fast, low-voltage operation. In this work, we address the processing challenges of integrating chemically incompatible PR and PE materials together within a surrounding cage against which the PR can be compressed. This proof-of-concept demonstration of a fully integrated, stand-alone PET device is a key step in the development path toward a fast, low-power very large scale integration technology.

We study the use of a simple three-leg molecule, triphenylene, as a transistor. This configuration allows increased voltage gain to be achieved. We analyze control of the transport between electrodes attached to two of the legs by a gate closely coupled electrostatically to the third leg, using self-consistent density functional calculations. In spite of the close coupling, the maximum voltage gain was less than unity, and this was attributed to efficient screening of the internal potential due to polarization of the molecular states. The transistor current vs. voltage characteristics were able to be reproduced using a simple electrostatic model.

We study transport and charge control in a gated 4,4'-biphenyl diradical molecular transistor using self-consistent density-functional calculations. We track both electron-like and hole-like conduction and relate it to the field dependence of current-carrying pi-derived states. Owing to the coupling between the two benzene rings, the pi-states become segregated into extended, current-carrying states and localized states. Under application of the source/drain field, along the axis of the molecule, the localized pi-states become split, while the extended states become polarized and screen the field. The localized states act like isolated islands within the molecule--while they make a substantial contribution to the density of states, they make only a small contribution to transport.

We study charge control in a gated 4,4'-biphenyl diradical molecular transistor using ab initio density functional theory calculations. I-V curves and intrinsic gate capacitances were derived. We find charge control in this transistor to be strongly affected by polarization of the sigma-states of the molecule, leading to strong electrostatic coupling of the internal potentials to the source and drain electrodes, and relatively weak coupling to the gate. We suggest that this spatially dependent and anisotropic polarization is an essential element in the operation of molecular transistors.