Technological Parameters and Edge Fringing Capacitance in GaN Schottky Barrier Diodes: Monte Carlo Simulations

[EN]Schottky barrier diodes (SBDs) with realistic geometries have been studied by means of a 2-D ensemble Monte Carlo simulator. The non-linearity of the Capacitance-Voltage (C-V) characteristic is the most important parameter for optimizing SBDs as frequency multipliers. In this paper, by changing the values of several technological parameters, we analyze their influence on the edge fringing capacitance in a GaN SBD. We have found that the parameters related with the dielectric used for the passivation and the lateral extension of the epilayer significantly affect the fringing capacitance, thus increasing the value of the total capacitance above the ideal one.Spanish MINECO and FEDER under Project TEC2017-83910-R and Junta de Castilla y León and FEDER under Project SA254P1

Massless Dirac fermions in III-V semiconductor quantum wells

We report on the clear evidence of massless Dirac fermions in two-dimensional system based on III-V semiconductors. Using a gated Hall bar made on a three-layer InAs/GaSb/InAs quantum well, we restore the Landau levels fan chart by magnetotransport and unequivocally demonstrate a gapless state in our sample. Measurements of cyclotron resonance at different electron concentrations directly indicate a linear band crossing at the $\Gamma$ point of Brillouin zone. Analysis of experimental data within analytical Dirac-like Hamiltonian allows us not only determing velocity $v_F=1.8\cdot10^5$ m/s of massless Dirac fermions but also demonstrating significant non-linear dispersion at high energies.Comment: Main text and Supplemental Materials, 14 pages, 9 figure

Influence of recess extension on double heterostructure metamorphic HEMT for power application at 60 GHz

This paper presents the influence of the recess extension on the power performance of double heterostructure Al0.65In0.35As/In0.35Ga0.65As/GaAs metamorphic HEMT’s in the millimeter wave range. Depending on the recess extension, devices exhibit an extrinsic cut-off frequency varying from 80 to 120 GHz. Output power measured at 60GHz with passive load pull bench can reach a power density of 340mW/mm with 6.5 dB linear gain and 21%PAE

Electroluminescence of metamorphic In x Al 1-x As / In x Ga 1-x As HEMTs ON GaAs substrate

We present the first impact ionization investigation by electroluminescence of InxAl1-xAs /InxGa1-xAs metamorphic High Electron Mobility transistors on GaAs. Two Indium content are investigated. First we observe the decrease of the detrimental effect of impact ionization with the decrease of the Indium content. Second, the electroluminescence measurements illuminate the functional relationship between impact ionization and the kink effect. In these metamorphic HEMT’s, we suggest that both kink effect and impact ionization threshold are originated to detrapping process of deep levels in the large band gap layer

Hemt structures and technology on GAAS and inp for power amplification in millimetre wave range

The paper introduces a simple and efficient approach for the modelling of low-frequency dispersive phenomena in FETs. It is based on the definition of a virtual, non-dispersive associated device controlled by equivalent port voltages and it is suitable for modelling based on standard nonlinear dynamic approaches, such as lumped-element equivalent circuits. The proposed approach is justified on the basis of a physically-consistent, charge-controlled description of the device, but the results are general and provide a valuable tool for taking into account dispersive effects in FETs by means of an intuitive circuit solution, in the framework of any existing nonlinear dynamic model of the associated non-dispersive device. The new equivalent-voltage description, identified on the basis of conventional measurements carried out under static and small-signal dynamic operating conditions, allows for the accurate prediction of dispersive effects above the frequency cut-off, but the formulation is still compatible, without for al modification, for the modelling of the device behaviour under signal excitations having spectral components in the dispersive low-frequency range. Preliminary results are presented which conferm the validity of the proposed approach

Power performance capability of metamorphic HEMT on GaAs substrate

An In0.3Al0.7As/In0.3Ga0.7As metamorphic power High Electron Mobility Transistor (HEMT) grown on GaAs has been developed. This structure with 30% indium content presents several advantages over PM-HEMT on GaAs and LM-HEMT on InP. A 0.15-um gate length device with a single S doping exhibits a current gain cut off frequency Ft value of 125 GHz at Vds = 1.5 V, an extrinsic transconductance of 650 mS/mm and a current density of 750 mA/mm associated to a high breakdown voltage of-13 V. Power measurements performed at 60 GHz demonstrate a maximum output power of 240 mW/mm with 6.4 dB power gain and a power added efficiency (PAE) of 25%. These are the first power results ever reported on any metamorphic HEMT