Fast Multiharmonic Active Load–Pull System With Waveform Measurement Capabilities

Thorsell, Mattias; Andersson, Kristoffer

doi:10.1109/tmtt.2011.2170090

Cited by 28 publications

(9 citation statements)

References 17 publications

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“…Large signal device characterization was carried out using an active load-pull setup [27] at a fundamental frequency of 3 GHz. The devices were biased in Class AB, with a quiescent current of 15% of I DSS and V DSQ = 15 V.…”

Section: G Load-pullmentioning

confidence: 99%

Dispersive Effects in Microwave AlGaN/AlN/GaN HEMTs With Carbon-Doped Buffer

Gustafsson

Chen

Bergsten

et al. 2015

IEEE Trans. Electron Devices

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Aluminium gallium nitride (AlGaN)/GaN high-electron mobility transistor performance is to a large extent affected by the buffer design, which, in this paper, is varied using different levels of carbon incorporation. Three epitaxial structures have been fabricated: 1) two with uniform carbon doping profile but different carbon concentration and 2) one with a stepped doping profile. The epitaxial structures have been grown on 4H-SiC using hot-wall metal-organic chemical vapor deposition with residual carbon doping. The leakage currents in OFF-state at 10 V drain voltage were in the same order of magnitude (10 −4 A/mm) for the high-doped and stepped-doped buffer. The high-doped material had a current collapse (CC) of 78.8% compared with 16.1% for the stepped-doped material under dynamic I-V conditions. The low-doped material had low CC (5.2%) but poor buffer isolation. Trap characterization revealed that the high-doped material had two trap levels at 0.15 and 0.59 eV, and the low-doped material had one trap level at 0.59 eV.Index Terms-Current collapse (CC), dispersion, gallium nitride (GaN), high-electron mobility transistor (HEMT), trap levels.

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Section: G Load-pullmentioning

confidence: 99%

Dispersive Effects in Microwave AlGaN/AlN/GaN HEMTs With Carbon-Doped Buffer

Gustafsson

Chen

Bergsten

et al. 2015

IEEE Trans. Electron Devices

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“…The LSNA enables vector corrected measurements with amplitude and phase information at the fundamental frequency as well as at higher order harmonics. 33 The delivered RF power (P in ) to the GND is measured at 1 GHz by the LSNA, and a voltage meter is used to measure the DC voltage across the diode generated by the nonlinearity (v DC ). The resulting vector corrected responsivity for various input powers is shown in Fig.…”

mentioning

confidence: 99%

High frequency electromagnetic detection by nonlinear conduction modulation in graphene nanowire diodes

Winters

Thorsell

Strupiński

et al. 2015

Applied Physics Letters

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We present graphene nanowires implemented as dispersion free self switched microwave diode detectors. The microwave properties of the detectors are investigated using vector corrected large signal measurements in order to determine the detector responsivity and noise equivalent power (NEP) as a function of frequency, input power, and device geometry. We identify two distinct conductance nonlinearities which generate detector responsivity: an edge effect nonlinearity near zero bias due to lateral gating of the nanowire structures, and a velocity saturation nonlinearity which generates current compression at high power levels. The scaling study shows that detector responsivity obeys an exponential scaling law with respect to nanowire width, and a peak responsivity (NEP) of 250 V/W (50 pW/ ffiffiffiffiffiffi Hz p ) is observed in detectors of the smallest width. The results are promising as the devices exhibit responsivities which are comparable to state of the art self switched detectors in semiconductor technologies. V C 2015 AIP Publishing LLC.

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“…Load-pull measurements were performed at 3 GHz (Fig. 3), with the setup described in [11]. The drain bias was set to 15 V and the load impedances were optimized for maximum output power.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of Thermal Versus Plasma-Assisted ALD Al<sub>2</sub>O<sub>3</sub> as Passivation for InAlN/AlN/GaN HEMTs

Malmros

Gamarra

Forte-Poisson

et al. 2015

IEEE Electron Device Lett.

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Al 2 O 3 films deposited by thermal and plasma-assisted atomic layer deposition (ALD) were evaluated as passivation layers for InAlN/AlN/GaN HEMTs. As a reference, a comparison was made with the more conventional plasma enhanced chemical vapor deposition deposited SiN x passivation. The difference in sheet charge density, threshold voltage, f T and f max was moderate for the three samples. The gate leakage current differed by several orders of magnitude, in favor of Al 2 O 3 passivation, regardless of the deposition method. Severe current slump was measured for the HEMT passivated by thermal ALD, whereas near-dispersion free operation was observed for the HEMT passivated by plasma-assisted ALD. This had a direct impact on the microwave output power. Large-signal measurements at 3 GHz revealed that HEMTs with Al 2 O 3 passivation exhibited 77% higher output power using plasma-assisted ALD compared with thermal ALD.

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Fast Multiharmonic Active Load–Pull System With Waveform Measurement Capabilities

Cited by 28 publications

References 17 publications

Dispersive Effects in Microwave AlGaN/AlN/GaN HEMTs With Carbon-Doped Buffer

Dispersive Effects in Microwave AlGaN/AlN/GaN HEMTs With Carbon-Doped Buffer

High frequency electromagnetic detection by nonlinear conduction modulation in graphene nanowire diodes

Evaluation of Thermal Versus Plasma-Assisted ALD Al<sub>2</sub>O<sub>3</sub> as Passivation for InAlN/AlN/GaN HEMTs

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