Minimum Noise Figure Fmin Research Articles

High‐speed and low‐noise AlInN/GaN HEMTs on SiC

AbstractA comparison of devices with different source–drain gaps has been performed on AlInN/GaN high electron mobility transistors (HEMTs) grown on SiC. The cut‐off frequency is effectively improved through shrinking source drain space and reducing gate parasitic capacitance. Our devices feature an fT of 188 GHz and fMAX of 200 GHz, which is the highest fMAX ever achieved to date for AlInN‐based HEMTs. At 10 (20) GHz, our HEMTs exhibit a low minimum noise figure Fmin of 0.62 (1.5) dB together with a high associated gain GA of 15.4 (13.3) dB. These Fmin values are among the lowest reported for deep submicrometer GaN HEMTs, and the GA are the best values so far in the literature, demonstrating the tremendous potential of AlInN/GaN HEMTs for microwave low‐noise applications.

Low-Noise Microwave Performance of 0.1 <formula formulatype="inline"> <tex Notation="TeX">$\mu$</tex></formula>m Gate AlInN/GaN HEMTs on SiC

We report the first microwave noise characterization of AlInN/GaN HEMTs. Transistors with a 0.1 μ m gate implemented on a semi-insulating SiC substrate achieve a maximum current density of 1.92 A/mm at <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</sub> = 0 V, a measured transconductance <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</sub> = 480 mS/mm, and a peak current gain cutoff frequency <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> = 121 GHz with a simultaneous maximum oscillation frequency <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</sub> = 142 GHz. At 10 (20) GHz, our HEMTs exhibit a minimum noise figure <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">F</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> of 0.62 (1.5) dB together with a high associated gain <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</sub> of 15.4 (13.3) dB. The <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">F</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> values are among the lowest reported in nitride HEMTs, and the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</sub> values are the best so far found in the literature, demonstrating the excellent potential of AlInN/GaN HEMTs for low-noise microwave applications.

Modeling of Degradation Effects on the High Frequency Noise of Metal–Oxide–Semiconductor Field-Effect Transistors

This paper proposes a hot-carrier stressed high-frequency noise model for metal–oxide–semiconductor field-effect transistors (MOSFETs). We first use the analytical method to develop a new fresh high-frequency noise model for MOSFETs, this model incorporates the effects of gate resistance, gate-induced current noise and non-local channel carrier heating, it can be used to calculate the minimum noise figure Fmin, optimized source admittance Yopt, and equivalent noise resistance Rn and admittance Gi. Secondly, we develop a new post-stress high-frequency noise model for MOSFETs, within this model the effects of hot-carrier stress induced interface states on the high-frequency noise performance can be evaluated. This model provides insightful device physics about the evolution of spatial noise sources within the channel versus stress time. The modeled results are in agreement with the experimental data of nMOSFETs with 0.25, 0.3 and 0.8-µm channel lengths.

Accurate charge‐control model for analysis of noise properties for AlGaAs/GaAs hemt and AlGaAs/InGaAs phemt at microwave frequencies

AbstractAn accurate charge‐control approach to analytical noise modeling of a high electron mobility transistor, which provides excellent results in agreement with the experimental data, is presented. The small‐signal parameters, and the drain and gate‐noise sources are calculated to determine the noise coefficients, minimum noise figure Fmin and minimum noise temperature Tmin. The influence of drain current, frequency, and device parameters upon Fmin and Tmin for AlGaAs/GaAs HEMT and AlGaAs/InGaAs/GaAs PHEMT is presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 489–494, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20346

High-frequency noise performance of SiGe p -channelMODFETs

For the first time, an investigation into the microwave noise performance of SiGe-based MODFETs is presented. The devices were 0.1 µm gate-length p-channel MODFETs fabricated on a high-mobility SiGe strained-layer heterostructure grown by UHV-CVD and had a unity gain cutoff frequency fT of 42 GHz and maximum frequency of oscillation fmax of 69 GHz at a drain-to-source bias voltage Vds of –0.6 V. A minimum noise figure Fmin of 1.1 dB and an associated gain Ga of 18 dB were obtained at 3 GHz, while values of Fmin = 1.7 dB and Ga = 12 dB were obtained at 10 GHz. These values are comparable to those of SiGe production HBTs, and demonstrate the suitability of SiGe MODFETs for RF and microwave communications applications.

Low-frequency low-noise circuits design using an E n-In model

In view of the limitations of a R n-Gn model in the low frequency range and the defects of an E n-In model in common use now, this paper builds a complete E n-In model according to the theory of random harmonic. The parameters for the low-noise design such as the equivalent input noisy voltage E ns, the optimum source impedance Z sopt and the minimum noise figure F min can be calculated accurately by using this E n-In model because it considers the coherence between the noise sources fully. Moreover, this paper points out that it will cause the maximum 30% miscalculation when neglecting the effects of the correlation coefficient γ. Using the series-series circuits as an example, this paper discusses the methods for the E n-In noise analysis of electronic circuits preliminarily and demonstrates its correctness through the comparison between the simulated and measured results of the minimum noise figure F min of a single current series negative feedback circuit.

Influence of GaAs buffer thickness on low-frequency and microwave noise in GaAs MESFETs grown on InP substrates

The dependence on the GaAs buffer layer thickness of the low and high frequency noise performance of GaAs MESFETs grown on InP substrates has been investigated. The 1/f noise magnitude at f = 1 kHz and the minimum noise figure Fmin in the 2–12 GHz frequency range, measured for a buffer layer thickness varying from 1 to 5 μm, decreases when the buffer thickness increases. The results obtained for a buffer thickness of 3 μm or more are close to those observed on bulk GaAs and are consistent with the GaAs layer crystalline improvement observed by X-ray diffraction measurements.