scholarly journals Microwave Analysis for Two-Dimensional C-V and Noise Model of AlGaN/GaN MODFET

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ramnish Kumar ◽  
Sandeep K. Arya ◽  
Anil Ahlawat
Keyword(s):  
Noise Figure ◽  
Noise Model ◽  
Gate Length ◽  
Two Dimensional ◽  
High Frequencies ◽  
Noise Characteristics ◽  
Proposed Model ◽  
Dimensional Electron Gas ◽  
High Transconductance ◽  
Gate Resistance

A new two-dimensional analytical model for the capacitance-voltage and noise characteristics of a AlGaN/GaN MODFET is developed. The two-dimensional electron gas density is calculated as a function of device dimensions. The model includes the spontaneous and polarization effects. The contribution of various capacitances to the performance of the device is shown. The model further predicts the transconductance, drain conductance, and frequency of operation. A high transconductance of 160 mS/mm and a cut-off frequency of 11.6 GHz are obtained for a device of 50 nm gate length. The effect of gate length on the gate length behaviour of the noise coefficientsP,R, andCis also studied. The effect of parasitic source and gate resistance has also been studied to evaluate the minimum noise figure. The excellent agreement with the previously simulated results confirms the validity of the proposed model to optimize the device performance at high frequencies.

scholarly journals Sensitivity Enhancement of NMR Spectroscopy Receiving Chain Used in Condensed Matter Physics

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3064 ◽  
Author(s):  
Petar Kolar ◽  
Mihael S. Grbić ◽  
Silvio Hrabar
Keyword(s):  
Nmr Spectroscopy ◽  
Noise Figure ◽  
Condensed Matter ◽  
A Priori ◽  
Noise Model ◽  
Measurement Time ◽  
Condensed Matter Physics ◽  
Noise Levels ◽  
Proposed Model ◽  
Optimized Conditions

Assurance of high measuring sensitivity is one of the most challenging issues for any nuclear magnetic resonance (NMR) spectroscopy system. To this end, we propose an accurate noise model of the entire probe-to-spectrometer receiving chain for condensed matter physics, based on the concept of noise figure. The model predicts the propagation of both the signal and noise levels in every component of the NMR spectroscopy receiving chain. Furthermore, it enables identification of the "weakest" component and, therefore, the optimization of the whole system. The most important property of the proposed model is the possibility to find system parameters that reduce the measurement time by an a priori calculation, rather than an a posteriori approach. The model was tested experimentally on several different samples. It was found that the measurement time can still be significantly shortened, down to at least one half of the measurement time, starting from optimized conditions with commercially available components. Thus, the proposed model can be used as a tool for both quantitative analysis of the noise properties and a sensitivity prediction of practical NMR systems in physics and material science.

scholarly journals Linear Characterization and Modeling of GaN-on-Si HEMT Technologies with 100 nm and 60 nm Gate Lengths

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 134
Author(s):  
Sergio Colangeli ◽  
Walter Ciccognani ◽  
Patrick Ettore Longhi ◽  
Lorenzo Pace ◽  
Julien Poulain ◽  
...  
Keyword(s):  
Test Bench ◽  
Linear Models ◽  
Noise Figure ◽  
Low Cost ◽  
Noise Temperature ◽  
Equivalent Circuit Model ◽  
Nondestructive Method ◽  
Noise Model ◽  
Gate Length ◽  
Gan On Si

Motivated by the growing interest towards low-cost, restriction-free MMIC processes suitable for multi-function, possibly space-qualified applications, this contribution reports the extraction of reliable linear models for two advanced GaN-on-Si HEMT technologies, namely OMMIC’s D01GH (100 nm gate length) and D006GH (60 nm gate length). This objective is pursued by means of both classical and more novel approaches. In particular, the latter include a nondestructive method for determining the extrinsic resistances and an optimizaion-based approach to extracting the remaining parasitic elements: these support standard DC and RF measurements in order to obtain a scalable, bias-dependent equivalent-circuit model capturing the small-signal behavior of the two processes. As to the noise model, this is extracted by applying the well known noise-temperature approach to noise figure measurements performed in two different frequency ranges: a lower band, where a standard Y-factor test bench is used, and an upper band, where a custom cold-source test bench is set up and described in great detail. At 5 V drain-source voltage, minimum noise figures as low as 1.5 dB and 1.1 dB at 40 GHz have been extracted for the considered 100 nm and 60 nm HEMTs, respectively: this testifies the maturity of both processes and the effectiveness of the gate length reduction. The characterization and modeling campaign, here presented for the first time, has been repeatedly validated by published designs, a couple of which are reviewed for the Reader’s convenience.

Anisotropic bilinear magnetoresistance in (110) SrTiO3 -based two-dimensional electron gas

2021 ◽  
Vol 104 (4) ◽  
Author(s):  
Jine Zhang ◽  
Hui Zhang ◽  
Xiaobing Chen ◽  
Jing Zhang ◽  
Shaojin Qi ◽  
...  
Keyword(s):  
Electron Gas ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Dimensional Electron Gas
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