Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

A 3-10-Ghz low-noise amplifier with wideband LC-ladder matching network

Author(s): Ahn, KH; Wu, XW; Liu, K; Chien, CL | Abstract: The effect of Fe doping (l20%) on the Mn site in the ferromagnetic ((Formula presented)) and the antiferromagnetic ((Formula presented)) phases of (Formula presented) has been studied. The same ionic radii of (Formula presented) and (Formula presented) cause no structure change in either series, yet conduction and ferromagnetism have been consistently suppressed by Fe doping. Colossal magnetoresistance has been shifted to lower temperatures, and in some cases enhanced by Fe doping. Doping with Fe bypasses the usually dominant lattice effects, but depopulates the hopping electrons and thus weakens the double exchange. © 1996 The American Physical Society.

Magnetic properties and colossal magnetoresistance of LaÑCaÖMnO3 materials doped with Fe

New developments in theoretical studies of defects and impurities in III-Nitrides as pertinent to compensation and recombination in these materials are discussed. New results on experimental studies on defect states of Si, O, Mg, C, Fe in GaN, InGaN, and AlGaN are surveyed. Deep electron and hole traps data reported for GaN and AlGaN are critically assessed. The role of deep defects in trapping in AlGaN/GaN, InAlN/GaN structures and transistors and in degradation of transistor parameters during electrical stress tests and after irradiation is discussed. The recent data on deep traps influence on luminescent efficiency and degradation of characteristics of III-Nitride light emitting devices and laser diodes are reviewed.

Deep traps in GaN-based structures as affecting the performance of GaN devices

Evolution of deep centers in GaN grown by hydride vapor phase epitaxy Z-Q. Fang and D.C. Look Semiconductor Research Center, Wright State University, Dayton, Ohio 45435 J. Jasinski, M. Benamara, and Z Liliental-Weber Lawrence Berkeley National Laboratory, Berkeley, California 94720 R.J. Molnar Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts Abstract Deep centers and dislocation densities in undoped n GaN, grown by hydride vapor phase epitaxy (HVPE), were characterized as a function of the layer thickness by deep level transient spectroscopy and transmission electron microscopy, respectively. As the layer thickness decreases, the variety and concentration of deep centers increase, in conjunction with the increase of dislocation density. Based on comparison with electron- irradiation induced centers, some dominant centers in HVPE GaN are identified as possible point defects.

/pdf/evolution-of-deep-centers-in-gan-grown-by-hydride-vapor-yqektycmmn.pdf

Evolution of deep centers in GaN grown by hydride vapor phase epitaxy - eScholarship

The conductivity of an $n$-type semiconductor has been calculated in the region of low-temperature $T$ and low impurity concentration ${n}_{D}$. The model is that of phonon-induced electron hopping from donor site to donor site where a fraction $K$ of the sites is vacant due to compensation. To first order in the electric field, the solution to the steady-state and current equations is shown to be equivalent to the solution of a linear resistance network. The network resistance is evaluated and the result shows that the $T$ dependence of the resistivity is $\ensuremath{\rho}\ensuremath{\propto}\mathrm{exp}(\frac{{\ensuremath{\epsilon}}_{3}}{\mathrm{kT}})$. For small $K$, ${\ensuremath{\epsilon}}_{3}=(\frac{{e}^{2}}{{\ensuremath{\kappa}}_{0}}){(\frac{4\ensuremath{\pi}{n}_{D}}{3})}^{\frac{1}{3}}(1\ensuremath{-}1.35{K}^{\frac{1}{3}})$, where ${\ensuremath{\kappa}}_{0}$ is the dielectric constant. At higher $K$, ${\ensuremath{\epsilon}}_{3}$ and $\ensuremath{\rho}$ attain a minimum near $K=0.5$. The dependence on ${n}_{D}$ is extracted; the agreement of the latter and of ${\ensuremath{\epsilon}}_{3}$ with experiment is satisfactory. The magnitude of $\ensuremath{\rho}$ is in fair agreement with experiment. The influence of excited donor states on $\ensuremath{\rho}$ is discussed.

Impurity Conduction at Low Concentrations.

In this work we report on the characteristics of a (Ni/Au)/AlGaN/GaN/SiC Schottky barrier diode (SBD). A variety of electrical techniques, such as gate current-voltage (I-V), capacitance-voltage (C-V), and deep level transient spectroscopy (DLTS) measurements have been used to characterize the diode. The behavior study of the series resistance, RS, the ideality factor, n, the effective barrier height, Φb, and the leakage current with the temperature have emphasized an inhomogeneity of the barrier height and a tunneling mechanism assisted by traps in the SBD. Hence, C-V measurements successively sweeping up and down the voltage have demonstrate a hysteresis phenomenon which is more pronounced in the temperature range of 240 to 320 K, with a maximum at ∼300 K. This parasitic effect can be attributed to the presence of traps activated at the same range of temperature in the SBD. Using the DLTS technique, we have detected one hole trap having an activation energy and a capture cross-section of 0.75 eV and 1.0...

Electrical characterization of (Ni/Au)/Al0.25Ga0.75N/GaN/SiC Schottky barrier diode

Double Jonscher response and contribution of multiple mechanisms in electrical conductivity processes of Fe-PrCaMnO ceramic

Investigation of traps in AlGaN/GaN HEMTs by current transient spectroscopy

Summerfield scaling model and conduction processes defining the transport properties of silver substituted half doped (La–Ca) MnO3 ceramic

In this paper, we report static electric drain-source current-voltage measurements for different gate voltages and at different temperatures, performed on Al0.25Ga0.75N/GaN/SiC high electron-mobility transistors (HEMT). The results show the presence of kink and collapse effects. We have demonstrated that these effects are significant in the temperature range varying from 150 to 400 K with a maximum around 300 K. This parasitic effect was correlated with the presence of deep levels in our transistor. Indeed, we have noticed the presence of two electron traps named A1 and A2, and one hole trap named H1; their respective activation energies, which are determined using current deep level transient spectroscopy (CDLTS), are, respectively, 0.56, 0.82, and 0.75 eV. Traps H1 and A1 are shown to be extended defects in the Al0.25Ga0.75N/GaN heterostructure; they are supposed to be the origin of the kink and collapse effects. However, the punctual defect A2 seems to be located either in the free gate-drain surface, ...

M. Gassoumi

Papers

Electrical characterization of (Ni/Au)/Al0.25Ga0.75N/GaN/SiC Schottky barrier diode

Double Jonscher response and contribution of multiple mechanisms in electrical conductivity processes of Fe-PrCaMnO ceramic

Investigation of traps in AlGaN/GaN HEMTs by current transient spectroscopy

Summerfield scaling model and conduction processes defining the transport properties of silver substituted half doped (La–Ca) MnO3 ceramic

Anomaly and defects characterization by I-V and current deep level transient spectroscopy of Al0.25Ga0.75N/GaN/SiC high electron-mobility transistors