scholarly journals An Experimental and Systematic Insight into the Temperature Sensitivity for a 0.15-µm Gate-Length HEMT Based on the GaN Technology

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 549
Author(s):  
Mohammad Abdul Alim ◽  
Christophe Gaquiere ◽  
Giovanni Crupi
Keyword(s):  
Ambient Temperature ◽  
Equivalent Circuit Model ◽  
Gate Length ◽  
Scattering Parameters ◽  
Temperature Dependent ◽  
Gan Hemt ◽  
Electron Transport Properties ◽  
The Impact ◽  
Insight Into ◽  
Microwave Characteristics

Presently, growing attention is being given to the analysis of the impact of the ambient temperature on the GaN HEMT performance. The present article is aimed at investigating both DC and microwave characteristics of a GaN-based HEMT versus the ambient temperature using measured data, an equivalent-circuit model, and a sensitivity-based analysis. The tested device is a 0.15-μm ultra-short gate-length AlGaN/GaN HEMT with a gate width of 200 μm. The interdigitated layout of this device is based on four fingers, each with a length of 50 μm. The scattering parameters are measured from 45 MHz to 50 GHz with the ambient temperature varied from −40 °C to 150 °C. A systematic study of the temperature-dependent performance is carried out by means of a sensitivity-based analysis. The achieved findings show that by the heating the transistor, the DC and microwave performance are degraded, due to the degradation in the electron transport properties.

Conformational and aggregation properties of PffBT4T polymers: atomistic insight into the impact of alkyl-chain branching positions

2019 ◽  
Vol 7 (45) ◽  
pp. 14198-14204
Author(s):  
Lu Ning ◽  
Guangchao Han ◽  
Yuanping Yi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Alkyl Chain ◽  
Temperature Dependent ◽  
Chain Branching ◽  
Alkyl Chains ◽  
Dynamics Simulations ◽  
The Impact ◽  
Insight Into

The impact of the branching positions of alkyl chains on temperature dependent aggregation is rationalized by atomistic molecular dynamics simulations.

scholarly journals Scaling Behavior of Sub-100 nm InAlN/GaN HEMTs on Silicon for RF Applications

2021 ◽  
Author(s):  
Peng Cui ◽  
Yuping Zeng
Keyword(s):  
Cutoff Frequency ◽  
Equivalent Circuit Model ◽  
Scaling Behavior ◽  
Gate Length ◽  
High Electron ◽  
Intrinsic Parameters ◽  
Gan Hemt ◽  
Gan Hemts ◽  
Rf Applications ◽  
20 Nm

Abstract Due to the low cost and the scaling capability of Si substrate, InAlN/GaN high-electron-mobility transistors (HEMTs) on silicon substrate have attracted more and more attentions. In this paper, a high-performance 50-nm-gate-length InAlN/GaN HEMT on Si with a high on/off current (Ion/Ioff) ratio of 7.28 × 106, an average subthreshold swing (SS) of 72 mV/dec, a low drain-induced barrier lowing (DIBL) of 88 mV, an off-state three-terminal breakdown voltage (BVds) of 36 V, a current/power gain cutoff frequency (fT/fmax) of 140/215 GHz, and a Johnson’s figure-of-merit (JFOM) of 5.04 THz∙V is simultaneously demonstrated. The device extrinsic and intrinsic parameters are extracted using equivalent circuit model, which is verified by the good agreement between simulated and measured S-parameter values. Then the scaling behavior of InAlN/GaN HEMTs on Si is predicted using the extracted extrinsic and intrinsic parameters of devices with different gate lengths (Lg). It presents that a fT/fmax of 230/327 GHz can be achieved when Lg­ scales down to 20 nm with the technology developed in the study, and an improved fT/fmax of 320/535 GHz can be achieved on a 20-nm-gate-length InAlN/GaN HEMT with regrown ohmic contact technology and 30% decreased parasitic capacitance. This study confirms the feasibility of further improvement of InAlN/GaN HEMTs on Si for RF applications.

AlNGaN HEMT T-Gate Optimal Design

2013 ◽  
Vol 347-350 ◽  
pp. 1790-1792
Author(s):  
Xiao Wei Zhang ◽  
Ke Jin Jia ◽  
Yuan Gang Wang ◽  
Zhi Hong Feng ◽  
Zheng Ping Zhao
Keyword(s):  
Optimal Design ◽  
High Frequency ◽  
Size Range ◽  
Gate Length ◽  
Maximum Oscillation Frequency ◽  
Gan Hemt ◽  
The Cost ◽  
Gate Resistance ◽  
The Impact ◽  
Gate Size

The GaN HEMT is widely used in high-frequency aspects, use the T-gate to reduce gate resistance is one of the most effective methods to improve the the device maximum oscillation frequency (fmax). But fmax is very sensitive to T-gate size, improper selection may reduce fmax, Therefore, in order to reduce the cost of production, it is necessary to select appropriate simulation T-gate size. We have worked out AlGaN/GaN HEMT with gate length of 0.17μm and fmax values 110GHz. Accuracy of the simulation model is verified by experiment. Then detailed simulates the impact of the T-gate size and we obtain ptimized T-gate size range.

scholarly journals Comparisons of IASI-A and AATSR measurements of top-of-atmosphere radiance over an extended period

2016 ◽  
Vol 9 (7) ◽  
pp. 3325-3336 ◽  
Author(s):  
Manik Bali ◽  
Jonathan P. Mittaz ◽  
Eileen Maturi ◽  
Mitchell D. Goldberg
Keyword(s):  
Spectral Response ◽  
Extended Period ◽  
Temperature Dependent ◽  
Orbital Maneuvers ◽  
Atmospheric Sounding ◽  
Along Track ◽  
The Impact ◽  
Temperature Time ◽  
Very High ◽  
Insight Into

Abstract. This study examines the trustworthiness of the Advanced Along-Track Scanning Radiometer (AATSR) and the Infrared Atmospheric Sounding Interferometer (IASI-A), as on-orbit reference instruments that are useful in re-calibrating the Advanced Very High Resolution Radiometer (AVHRR) series (Mittaz and Harris, 2011). To do this, a 39-month period (1 January 2008 to 31 March 2011) of AATSR and IASI-A inter-comparisons of top-of-atmosphere (TOA) radiance measurements is examined. Our inter-comparison reveals features of the AATSR and IASI-A bias with respect to scan angle, scene temperature, time and orbital maneuvers, and gives insight into their trustworthiness as an in-orbit reference instruments. The first feature that our study reveals is that the AATSR (nadir view) and IASI-A are both stable (have no perceptible trends in the period of study). The second feature is that IASI-A is perhaps more accurate ( ∼  0.05 K) than its stated accuracy (0.5 K). In fact the AATSR and IASI-A bias is close to the AATSR pre-launch bias (plus a small offset of +0.07 K) implying that IASI-A can get close to pre-launch levels of accuracy. Third, a very small scan angular dependence of AATSR and IASI-A bias indicates that the IASI-A response vs. scan angle algorithm is robust, while the instrument is in orbit. Inter-comparisons of AATSR with IASI-A further reveal the impact of orbital maneuvers of the ENVISAT, the platform carrying AATSR, done in October 2011 and not anticipated previously. Our study reveals that this maneuver introduced a temperature-dependent bias in the AATSR measurements for low temperatures (< 240 K) in the period following this maneuver (Cocevar et al., 2011). Our study also shows that the known AATSR 12 µm channel offset is in fact temperature dependent, grows up to 0.4 K, varies seasonally and is correlated with instrument temperature and cannot be corrected by shifting the spectral response function (SRF) of AATSR. We also present a set of recommendations to help identify the parameters under which these instruments can provide the most trustworthy observations for the AVHRR re-calibration.

scholarly journals Scaling Behavior of InAlN/GaN HEMTs on Silicon for RF Applications

2022 ◽  
Author(s):  
Peng Cui ◽  
Yuping Zeng
Keyword(s):  
Cutoff Frequency ◽  
Equivalent Circuit Model ◽  
Scaling Behavior ◽  
Gate Length ◽  
High Electron ◽  
Intrinsic Parameters ◽  
Gan Hemt ◽  
Gan Hemts ◽  
Rf Applications ◽  
20 Nm

Abstract Due to the low cost and the scaling capability of Si substrate, InAlN/GaN high-electron-mobility transistors (HEMTs) on silicon substrate have attracted more and more attentions. In this paper, a high-performance 50-nm-gate-length InAlN/GaN HEMT on Si with a high on/off current (Ion/Ioff) ratio of 7.28 × 106, an average subthreshold swing (SS) of 72 mV/dec, a low drain-induced barrier lowing (DIBL) of 88 mV, an off-state three-terminal breakdown voltage (BVds) of 36 V, a current/power gain cutoff frequency (fT/fmax) of 140/215 GHz, and a Johnson’s figure-of-merit (JFOM) of 5.04 THz∙V is simultaneously demonstrated. The device extrinsic and intrinsic parameters are extracted using equivalent circuit model, which is verified by the good agreement between simulated and measured S-parameter values. Then the scaling behavior of InAlN/GaN HEMTs on Si is predicted using the extracted extrinsic and intrinsic parameters of devices with different gate lengths (Lg). It presents that a fT/fmax of 230/327 GHz can be achieved when Lg­ scales down to 20 nm with the technology developed in the study, and an improved fT/fmax of 320/535 GHz can be achieved on a 20-nm-gate-length InAlN/GaN HEMT with regrown ohmic contact technology and 30% decreased parasitic capacitance. This study confirms the feasibility of further improvement of InAlN/GaN HEMTs on Si for RF applications.

An ambient temperature dependent small signal model of GaN HEMT using method of curve fitting

2020 ◽  
Vol 30 (12) ◽  
Author(s):  
Arijit Majumdar ◽  
Soumyo Chatterjee ◽  
Sayan Chatterjee ◽  
Sheli Sinha Chaudhari ◽  
Dipak Ranjan Poddar
Keyword(s):  
Ambient Temperature ◽  
Curve Fitting ◽  
Small Signal ◽  
Temperature Dependent ◽  
Signal Model ◽  
Gan Hemt ◽  
Small Signal Model

scholarly journals Changing landscapes: Gay men in the west and northwest of Ireland

Sexualities ◽  
2020 ◽  
pp. 136346072098169
Author(s):  
Aidan McKearney
Keyword(s):  
Gay Men ◽  
Social Rights ◽  
Irish Society ◽  
Recent Past ◽  
Same Sex ◽  
Lgbt People ◽  
The Many ◽  
Northwest Region ◽  
The Impact ◽  
Insight Into

This article focuses on the experiences of gay men in the rural west and northwest region of Ireland, during a period of transformational social and political change in Irish society. These changes have helped facilitate new forms of LGBTQI visibility, and local radicalism in the region. Same-sex weddings, establishment of rural LGBT groups and marching under an LGBT banner at St Patricks Day parades would have been unthinkable in the recent past; but they are now becoming a reality. The men report continuing challenges in their lives as gay men in the nonmetropolitan space, but the emergence of new visibility, voice and cultural acceptance of LGBT people is helping change their lived experiences. The study demonstrates the impact of local activist LGBT citizens. Through their testimonies we can gain an insight into the many, varied and interwoven factors that have interplayed to create the conditions necessary for the men to: increasingly define themselves as gay to greater numbers of people in their localities; to embrace greater visibility and eschew strategies of silence; and aspire to a host of legal, political, cultural and social rights including same-sex marriage. Organic forms of visibility and local radicalism have emerged in the region and through an analysis of their testimonies we can see how the men continue to be transformed by an ever-changing landscape.

Double, triple or quadruple hits? Exploring the impact of cybercrime on victims in the Netherlands

2021 ◽  
pp. 026975802110106
Author(s):  
Raoul Notté ◽  
E.R. Leukfeldt ◽  
Marijke Malsch
Keyword(s):  
Public Opinion ◽  
Literature Review ◽  
The Netherlands ◽  
Public Discourse ◽  
Moral Judgments ◽  
Victim Blaming ◽  
High Prevalence ◽  
Different Types ◽  
The Impact ◽  
Insight Into

This article explores the impact of online crime victimisation. A literature review and 41 interviews – 19 with victims and 22 with experts – were carried out to gain insight into this. The interviews show that most impacts of online offences correspond to the impacts of traditional offline offences. There are also differences with offline crime victimisation. Several forms of impact seem to be specific to victims of online crime: the substantial scale and visibility of victimhood, victimisation that does not stop in time, the interwovenness of online and offline, and victim blaming. Victims suffer from double, triple or even quadruple hits; it is the accumulation of different types of impact, enforced by the limitlessness in time and space, which makes online crime victimisation so extremely invasive. Furthermore, the characteristics of online crime victimisation greatly complicate the fight against and prevention of online crime. Finally, the high prevalence of cybercrime victimisation combined with the severe impact of these crimes seems contradictory with public opinion – and associated moral judgments – on victims. Further research into the dominant public discourse on victimisation and how this affects the functioning of the police and victim support would be valuable.

scholarly journals Design of a Novel Miniaturized Frequency Selective Surface Based on 2.5-Dimensional Jerusalem Cross for 5G Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Peng Zhao ◽  
Yihang Zhang ◽  
Rongrong Sun ◽  
Wen-Sheng Zhao ◽  
Yue Hu ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Equivalent Circuit ◽  
Equivalent Circuit Model ◽  
Frequency Selective Surface ◽  
Size Reduction ◽  
Two Dimensional ◽  
Physical Insight ◽  
Frequency Selective ◽  
Significant Size ◽  
Insight Into

A compact frequency selective surface (FSS) for 5G applications has been designed based on 2.5-dimensional Jerusalem cross. The proposed element consists of two main parts: the successive segments of the metal traces placed alternately on the two surfaces of the substrate and the vertical vias connecting traces. Compared with previous published two-dimensional miniaturized elements, the transmission curves indicate a significant size reduction (1/26 wavelengths at the resonant frequency) and exhibit good angular and polarization stabilities. Furthermore, a general equivalent circuit model is established to provide direct physical insight into the operating principle of this FSS. A prototype of the proposed FSS has been fabricated and measured, and the results validate this design.

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