Metal-Semiconductor Contacts and CPW MMIC Issues for AlGaN/GaN FETs

2000 ◽  
Vol 639 ◽  
Author(s):  
Bart Jacobs ◽  
Mark Kramer ◽  
Bram van Straaten ◽  
Thieu Kwaspen ◽  
Fouad Karouta ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Amplifiers ◽  
Systematic Investigation ◽  
Coplanar Waveguides ◽  
Output Stage ◽  
Cross Sectional ◽  
Hybrid Solution ◽  
Semiconductor Contacts ◽  
Heavily Doped ◽  
Via Hole

ABSTRACTIn this report two different aspects in the development of AlGaN/GaN power amplifiers will be discussed. In the first part of this paper we report on the optimization of the Ti/Al/Ni/Au metallization scheme on a doped AlGaN/GaN FET structure. By a systematic investigation we were able to reduce the contact resistance to 0.2 ωmm (7.3×10×7ωcm2). The Al/Ti thickness ratio for this contact was 6, which according to the Al-Ti binary phase diagram, does not result in excess Ti which should react with nitrogen in the AlGaN layer to render the surface heavily doped. Preliminary results on Schottky contacts indicate an improvement in the reverse leakage current if a RIE oxygen plasma in combination with a NH4OH dip is performed prior to metallization.Coplanar waveguides on AlN are discussed in the second part of this paper. These transmission lines can be used in AlGaN/GaN power amplifiers if no via-hole technology is available or if a hybrid solution is pursued. The signal line should have a large metal cross- sectional area (> 5 × 50 [.proportional]m2) in order to carry enough current in the output stage of an amplifier. It is shown that CPWs with large dimensions show non-quasi TEM behavior related to propagation of parallel plate modes.

scholarly journals Anemia among Chinese patients with chronic kidney disease and its association with quality of life - results from the Chinese cohort study of chronic kidney disease (C-STRIDE)

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yan Shen ◽  
◽  
Jinwei Wang ◽  
Jing Yuan ◽  
Li Yang ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Chronic Kidney Disease ◽  
Cohort Study ◽  
Kidney Disease ◽  
Systematic Investigation ◽  
Chinese Patients ◽  
Cross Sectional ◽  
Five Dimensions ◽  
Anemia Treatment

Abstract Background Anemia is one of the common complications in patients with chronic kidney disease (CKD). However, there is no systematic investigation on the prevalence of anemia in CKD patients and its relationship with the quality of life in China. Methods The data for this study comes from baseline data from the Chinese Chronic Kidney Disease Cohort Study (C-STRIDE), which recruited predialysis CKD patients in China. The kidney disease quality of life summary (KDQOL-TM) was used to assess health-related quality of life (HRQoL). Use linear regression model to estimate the relationship between hemoglobin level and quality of life. Results A total of 2921 patients were included in this study. The adjusted prevalence of hemoglobin (Hb) less than 100 g/L was 10.3% (95% confidence interval [CI]: 9.9,11.4%), and showed an increased trend through reduced eGFR levels from 4.0% (95%CI:2.3,5.9%) in the 45-60 ml/min/1.73m2 group to 23.4% (95%CI:20.5,26.2%) in the 15–29 ml/min/1.73m2 group. The prevalence of anti-anemia treatment was 34.0% (95%CI: 28.7,39.3%) and it is shown by reducing eGFR levels from 15.8% (95%CI:0,36.7%) in the 45-60 ml/min/1.73m2 group to 38.2% (95%CI: 30.7,45.2%) in the 15–29 ml/min/1.73m2 group. All five dimensions of the KDQOL scores in patients with CKD decreased as hemoglobin declined. After multivariable adjustments,the degrees of decrease became somewhat blunted. For example, compared with hemoglobin of ≥130 g/L, regression coefficients in the hemoglobin of < 100 g/L were − 0.047(95%CI: − 0.049,-0.045) for Symptoms and Problems(S), − 0.047(95%CI: − 0.049,-0.044) for Effects of the Kidney Disease(E), − 0.207(95%CI: − 0.212,-0.203) for Burden of the Kidney Disease(B), − 0.112(95%CI: − 0.115,-0.109) for SF-12 Physical Functioning (PCS), − 0.295(95%CI: − 0.299, -0.292) for SF-12 Mental Functioning (MCS), respectively. Conclusions In our cross-sectional analysis of patients with CKD in China, prevalence of both anemia and anti-anemia treatment increased with decreased eGFR. In addition, anemia was associated with reduced HRQoL.

scholarly journals Incidence and management of inguinodynia after inguinal plasty

2020 ◽  
Vol 8 (10) ◽  
pp. 3432
Author(s):  
Juan J. Granados-Romero ◽  
Jesus C. Ceballos-Villalva ◽  
Israel García-Olivo ◽  
Cruz Escobar Jonathan E. ◽  
María J. Corona-Torres ◽  
...  
Keyword(s):  
Hospital Costs ◽  
Laparoscopic Approach ◽  
Systematic Investigation ◽  
Pain Scale ◽  
Diagnostic Methods ◽  
Visual Analogue Pain Scale ◽  
Open Approach ◽  
Cross Sectional ◽  
Visual Analogue Pain ◽  
Quality Life

Background: Hernia is defined as a defect of fascial and muscle-aponeurotic structures, allowing the protrusion of elements. The most frequent is inguinal region, prevailing in men 3:1 vs female. The most frequent complications are persistent chronic pain.Methods: A descriptive, prospective and cross-sectional study was performed in postoperative inguinal plasty patients, using a laparoscopic approach and open approach, the presence or absence of inguinodynia was studied using the visual analogue pain scale (VAS) and the Semmes-Weinstein monofilament, in addition to a systematic investigation in the following PubMed, Medline, Clinical Key and Index Medicus databases, with articles from July 2019 to April 2020.Results: Inguinodynia was present in laparoscopic surgery and open approach, 58 patients had inguinodynia at two weeks associated with the inflammatory response of the tissues and the presence of a foreign body (mesh), 77% of the patients with persistence of pain at 3 months reported mild pain (VAS 1-4), 21% moderate pain that did not limit their daily activities (VAS 5-8) and 2% of the patients reported severe pain which limited physical activity and effort   (VAS 9-10).Conclusions: Inguinodynia has an impact on hospital costs and quality life, we consider it is essential to domain the anatomical variants of the region. We propose an extensive follow-up of this group of patients, to make a comparison of diagnostic methods, as well as conservative management vs. modern techniques for pain control.

scholarly journals Heavily-Doped Bulk Silicon Sidewall Electrodes Embedded between Free-Hanging Microfluidic Channels by Modified Surface Channel Technology

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 561
Author(s):  
Yiyuan Zhao ◽  
Henk-Willem Veltkamp ◽  
Thomas V. P. Schut ◽  
Remco G. P. Sanders ◽  
Bogdan Breazu ◽  
...  
Keyword(s):  
Thin Film ◽  
Silicon Substrate ◽  
Microfluidic Channels ◽  
Bulk Silicon ◽  
Sensors And Actuators ◽  
Cross Sectional ◽  
Mask Design ◽  
Electrical Sensing ◽  
Innovative Idea ◽  
Heavily Doped

Surface Channel Technology is known as the fabrication platform to make free-hanging microchannels for various microfluidic sensors and actuators. In this technology, thin film metal electrodes, such as platinum or gold, are often used for electrical sensing and actuation purposes. As a result that they are located at the top surface of the microfluidic channels, only topside sensing and actuation is possible. Moreover, in microreactor applications, high temperature degradation of thin film metal layers limits their performance as robust microheaters. In this paper, we report on an innovative idea to make microfluidic devices with integrated silicon sidewall electrodes, and we demonstrate their use as microheaters. This is achieved by modifying the original Surface Channel Technology with optimized mask designs. The modified technology allows to embed heavily-doped bulk silicon electrodes in between the sidewalls of two adjacent free-hanging microfluidic channels. The bulk silicon electrodes have the same electrical properties as the extrinsic silicon substrate. Their cross-sectional geometry and overall dimensions can be designed by optimizing the mask design, hence the resulting resistance of each silicon electrode can be customized. Furthermore, each silicon electrode can be electrically insulated from the silicon substrate. They can be designed with large cross-sectional areas and allow for high power dissipation when used as microheater. A demonstrator device is presented which reached 119.4 ∘ C at a power of 206.9 m W , limited by thermal conduction through the surrounding air. Other potential applications are sensors using the silicon sidewall electrodes as resistive or capacitive readout.

Prediction and Suppression of Twisted-wire Pair Crosstalk Based on Beetle Swarm Optimization Algorithm

2021 ◽  
Vol 36 (4) ◽  
pp. 435-441
Author(s):  
Jianming Zhou ◽  
Shijin Li ◽  
Wu Zhang ◽  
Wei Yan ◽  
Yang Zhao ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Unit Length ◽  
Back Propagation ◽  
Telegraph Equation ◽  
Frequency Domain Method ◽  
Cross Sectional ◽  
Swarm Optimization ◽  
Value Decomposition ◽  
Sectional Shape ◽  
Twisted Wire

Based on the theory of multi-conductor transmission lines (MTL), this paper proposes a new method for predicting and suppressing crosstalk of twisted-wire pair (TWP). The per unit length (p.u.l) RLCG parameters change caused by the inconsistent cross-sectional shape of TWP, changes in parameters make it difficult to solve the telegraph equation. In this paper, the method of transmission lines cascade is used. TWP is divided into several segments, and p.u.l parameters of each segment are predicted. Compared with before method, we propose a higher precision algorithm—beetle swarm optimization (BSO) to optimize the weights of back-propagation (BP) neural network, which predict p.u.l parameters at each segment. On this basis, it is divided into two steps: 1) Use MTL frequency domain method combined with lines’ terminal conditions to solve crosstalk and compare with CST simulation results; 2) Use the singular value decomposition (SVD) method to add matrix modules at both ends of lines for suppressing crosstalk. The results show that proposed method in this paper is consistent with the simulation, and the accuracy is higher than before

Interface structure and formation between gold and trimethylcyclohexane polycarbonate

1999 ◽  
Vol 14 (9) ◽  
pp. 3538-3543 ◽  
Author(s):  
C. v. Bechtolsheim ◽  
V. Zaporojtchenko ◽  
F. Faupel
Keyword(s):  
Photoelectron Spectroscopy ◽  
Elevated Temperatures ◽  
Cluster Formation ◽  
Systematic Investigation ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Metal Diffusion ◽  
Atomic Force ◽  
Transmission Electron

This paper presents the results of a systematic investigation of structure and formation of the interface between gold and trimethylcyclohexane polycarbonate, particularly concerning interface evolvement during gold evaporation and the influence of evaporation rate, substrate temperature, and subsequent annealing. The means of investigation were cross-sectional transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. Extensive metal diffusion into the polymer and cluster formation near the interface were observed at deposition rates of the order of one monolayer per minute and below. The penetration depth is strongly temperature dependent. At high evaporation rates metal aggregation at the surface prevents cluster formation inside the polymer. No diffusion into the polymer was observed from metal films deposited at room temperature after extensive annealing at elevated temperatures.

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