Effect of impact ionization in scaled pHEMTs

The effect of impact ionization on pseudomorphic high electron mobility transistors is studied using Monte Carlo simulations when these devices are scaled into deep decanano dimensions. The scaling of devices with gate lengths of 120, 90, 70, 50 and 30 nm has been performed in both lateral and vertical directions. The impact ionization is treated as an additional scattering mechanism in the Monte Carlo module. The critical drain voltage, at which device characteristics begin to indicate breakdown, decreases as the gate voltage is lowered. Similarly, the breakdown drain voltage is also found to decrease during the scaling process

RF analysis of aggressively scaled pHEMTs

No abstract avaliable

Optimizations of sub-100 nm Si/SiGe MODFETs for high linearity RF applications

Based on careful calibration in respect of 70 nm n-type strained Si channel S/SiGe modulation doped FETs (MODFETs) fabricated by Daimler Chrysler, numerical simulations have been used to study the impact of the device geometry and various doping strategies on device performance and linearity. The device geometry is sensitive to both RF performance and device linearity. Doped channel devices are found to be promising for high linearity applications. Trade-off design strategies are required for reconciling the demands of high device performance and high linearity simultaneously. The simulations also suggest that gate length scaling helps to achieve higher RF performance, but decreases the linearity

Self-aligned 0.12mm T-gate In.53Ga.47As/In.52Al.48As HEMT Technology Utilising a Non Annealed Ohmic Contact Strategy

An InGaAs/InAlAs based HEMT structure, lattice matched to an InP substrate, is presented in which drive current and transconductance has been optimized through a double-delta doping strategy. Together with an increase in channel carrier density, this allows the use of a non-annealed ohmic contact process. HEMT devices with 120 nm standard and self-aligned T-gates were fabricated using the non-annealed ohmic process. At DC, self-aligned and standard devices exhibited transconductances of up to 1480 and 1100 mS/mm respectively, while both demonstrated current densities in the range 800 mA/mm. At RF, a cutoff frequency f/sub T/ of 190 GHz was extracted for the self-aligned device. The DC characteristics of the standard devices were then calibrated and modelled using a compound semiconductor Monte Carlo device simulator. MC simulations provide insight into transport within the channel and illustrate benefits over a single delta doped structure

RF analysis of aggressively scaled pHEMTs

No abstract avaliable

A new two-phase dimeticone pediculicide shows high efficacy in a comparative bioassay

Background: \ud Dimeticones kill head lice by physical means. Here we assessed in a comparative bioassay the ex vivo efficacy of "NYDA® sensitiv", a new two-phase dimeticone-based pediculicide similar to a product established on the market, but without fragrances.\ud \ud Methods:\ud We compared efficacy of the new product to a positive dimeticone control group, a sample of four other insecticidal and natural head lice products marketed in Germany, and an untreated control. In a bioassay, lice were exposed ex vivo to products and examined for activity for up to 24 hours, following a standard protocol.\ud \ud Results:\ud After 6 and 24 hours, 13.7 and 88.5% of untreated control lice did not show major vital signs. In contrast, no lice showed major vital signs 5 minutes after treatment with the new product or the control dimeticone group (NYDA®). This effect persisted at all observation points (100% efficacy). Efficacy of 0.5% permethrin (Infectopedicul®) ranged between 76 and 96% in evaluations between 5 min and 6 hours. All lice treated with a coconut-based compound (mosquito® Läuseshampoo) did not show major vital signs after 5 min, but mortality was only 58% after one hour. Pyrethrum extract (Goldgeist® forte) showed an efficacy of 22 - 52% between 5 min and 3 hours after treatment; after 6 hours, 76% of lice were judged dead. An oxyphthirine®-based compound (Liberalice DUO LP-PRO®) killed 22 - 54% of lice in the first 6 hours.\ud \ud Conclusions:\ud The two-phase dimeticone compound NYDA® sensitiv is highly efficacious. The removal of fragrances as compared to an established dimeticone product did not affect in vitro efficacy

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum