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

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.

Author(s):  
Asmaa Nur Aqilah Zainal Badri ◽  
Norlaili Mohd Noh ◽  
Shukri Bin Korakkottil Kunhi Mohd ◽  
Asrulnizam Abd Manaf ◽  
Arjuna Marzuki ◽  
...  

<p>This study reviews related studies on the impact of the layout dependent effects on high frequency and RF noise parameter performances, carried out over the past decade. It specifically focuses on the doughnut and multi- finger layouts. The doughnut style involves the polygonal and the 4- sided techniques, while the multi-finger involving the narrow-oxide diffusion (OD) and multi-OD. The polygonal versus 4-sided doughnut, and the narrow-OD with multi-fingers versus multi-OD with multi- fingers are reviewed in this study. The high frequency parameters, which are of concern in this study, are the cut- off frequency (f<sub>T</sub>) and the maximum frequency (f<sub>MAX</sub>), whereas the noise parameters involved are noise resistance (R<sub>N</sub>) and the minimum noise figure (NF<sub>min</sub>). In addition, MOSFET parameters, which are affected by the layout style that in turn may contribute to the changes in these high frequency, and noise parameters are also detailed. Such parameters include transconductance (G<sub>m</sub>); gate resistance (R<sub>g</sub>); effective mobility (μ<sub>eff</sub>); and parasitic capacitances (c<sub>gg</sub> and c<sub>gd</sub>). Investigation by others has revealed that the polygonal doughnut may have a larger total area in comparison with the 4- sided doughnut. It is also found by means of this review that the multi-finger layout style with narrow-OD and high number of fingers may have the best performance in f<sub>T</sub> and f<sub>MAX</sub>, owing partly to the improvement in G<sub>m</sub>, μ<sub>eff</sub>, c<sub>gg</sub>, c<sub>gd</sub> and low frequency noise (LFN). A multi-OD with a lower number of fingers may lead to a lower performance in f<sub>T</sub> due to a lower G<sub>m</sub>. Upon comparing the doughnut and the multi-finger layout styles, the doughnuts appeared to perform better than a standard multi-finger layout for f<sub>T</sub>, f<sub>MAX</sub>, G<sub>m</sub> and μ<sub>eff</sub> but are poorer in terms of LFN. It can then be concluded that the narrow-OD multi-finger may cause the increase of c<sub>gg</sub> as the transistor becomes narrower, whereas a multi-OD multi-finger may have high R<sub>g</sub> and therefore may lead to the increase of f<sub>T</sub> and f<sub>MAX</sub> as the transistor becomes narrower. Besides, the doughnut layout style has a higher G<sub>m</sub> and f<sub>T</sub>, leading to larger μ<sub>eff</sub> from the elimination of shallow trench isolation (STI) stress.</p>


Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 549
Author(s):  
Mohammad Abdul Alim ◽  
Christophe Gaquiere ◽  
Giovanni Crupi

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.


1998 ◽  
Author(s):  
Kendall Scott Wills ◽  
Hal Edwards ◽  
Long Nuygen ◽  
Rohini Raghunathan ◽  
Charles Todd ◽  
...  

Abstract This article analyzes the cause of Vcc shorts in advanced microprocessors. In one instance, an advanced microprocessor exhibited Vcc shorts at wafer sort in a unique pattern. The poly silicon was narrow in one section of the die. The gates were shown to measure small, but no electrical proof of the short could be seen. To prove the short existed as a result of the narrow gate, a Scanning Capacitance Microscope (SCM) was utilized to confirm electrical models, which indicated a narrow poly silicon gate would result in Vcc shorts. High frequency dry etching and UV-ozone oxidation were employed for deprocessing. The use of the SCM confirmed the proof that the Vcc shorts were caused by narrow gate length which causes its leaky behavior. This conclusion could have only been confirmed by processing of material through the wafer foundry at the cost of money and time.


Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1159
Author(s):  
Lung-Hsing Hsu ◽  
Yung-Yu Lai ◽  
Po-Tsung Tu ◽  
Catherine Langpoklakpam ◽  
Ya-Ting Chang ◽  
...  

GaN HEMT has attracted a lot of attention in recent years owing to its wide applications from the high-frequency power amplifier to the high voltage devices used in power electronic systems. Development of GaN HEMT on Si-based substrate is currently the main focus of the industry to reduce the cost as well as to integrate GaN with Si-based components. However, the direct growth of GaN on Si has the challenge of high defect density that compromises the performance, reliability, and yield. Defects are typically nucleated at the GaN/Si heterointerface due to both lattice and thermal mismatches between GaN and Si. In this article, we will review the current status of GaN on Si in terms of epitaxy and device performances in high frequency and high-power applications. Recently, different substrate structures including silicon-on-insulator (SOI) and engineered poly-AlN (QST®) are introduced to enhance the epitaxy quality by reducing the mismatches. We will discuss the development and potential benefit of these novel substrates. Moreover, SOI may provide a path to enable the integration of GaN with Si CMOS. Finally, the recent development of 3D hetero-integration technology to combine GaN technology and CMOS is also illustrated.


2014 ◽  
Vol 84 (5-6) ◽  
pp. 244-251 ◽  
Author(s):  
Robert J. Karp ◽  
Gary Wong ◽  
Marguerite Orsi

Abstract. Introduction: Foods dense in micronutrients are generally more expensive than those with higher energy content. These cost-differentials may put low-income families at risk of diminished micronutrient intake. Objectives: We sought to determine differences in the cost for iron, folate, and choline in foods available for purchase in a low-income community when assessed for energy content and serving size. Methods: Sixty-nine foods listed in the menu plans provided by the United States Department of Agriculture (USDA) for low-income families were considered, in 10 domains. The cost and micronutrient content for-energy and per-serving of these foods were determined for the three micronutrients. Exact Kruskal-Wallis tests were used for comparisons of energy costs; Spearman rho tests for comparisons of micronutrient content. Ninety families were interviewed in a pediatric clinic to assess the impact of food cost on food selection. Results: Significant differences between domains were shown for energy density with both cost-for-energy (p < 0.001) and cost-per-serving (p < 0.05) comparisons. All three micronutrient contents were significantly correlated with cost-for-energy (p < 0.01). Both iron and choline contents were significantly correlated with cost-per-serving (p < 0.05). Of the 90 families, 38 (42 %) worried about food costs; 40 (44 %) had chosen foods of high caloric density in response to that fear, and 29 of 40 families experiencing both worry and making such food selection. Conclusion: Adjustments to USDA meal plans using cost-for-energy analysis showed differentials for both energy and micronutrients. These differentials were reduced using cost-per-serving analysis, but were not eliminated. A substantial proportion of low-income families are vulnerable to micronutrient deficiencies.


2014 ◽  
Vol 1 (2) ◽  
pp. 187
Author(s):  
Serdar KUZU

The size of international trade continues to extend rapidly from day to day as a result of the globalization process. This situation causes an increase in the economic activities of businesses in the trading area. One of the main objectives of the cost system applied in businesses is to be able to monitor the competitors and the changes that can be occured as a result of the developments in the sector. Thus, making cost accounting that is proper according to IAS / IFRS and tax legislation has become one of the strategic targets of the companies in most countries. In this respect, businesses should form their cost and pricing systems according to new regulations. Transfer pricing practice is usefull in setting the most proper price for goods that are subject to the transaction, in evaluating the performance of the responsibility centers of business, and in determining if the inter-departmental pricing system is consistent with targets of the business. The taxing powers of different countries and also the taxing powers of different institutions in a country did not overlap. Because of this reason, bringing new regulations to the tax system has become essential. The transfer pricing practice that has been incorporated into the Turkish Tax System is one of the these regulations. The transfer pricing practice which includes national and international transactions has been included in the Corporate Tax Law and Income Tax Law. The aim of this study is to analyse the impact of goods and services transfer that will occur between departments of businesses on the responsibility center and business performance, and also the impact of transfer pricing practice on the business performance on the basis of tax-related matters. As a result of the study, it can be said that transfer pricing practice has an impact on business performance in terms of both price and tax-related matters.


2015 ◽  
Vol 6 (1) ◽  
pp. 50-57
Author(s):  
Rizqa Raaiqa Bintana ◽  
Putri Aisyiyah Rakhma Devi ◽  
Umi Laili Yuhana

The quality of the software can be measured by its return on investment. Factors which may affect the return on investment (ROI) is the tangible factors (such as the cost) dan intangible factors (such as the impact of software to the users or stakeholder). The factor of the software itself are assessed through reviewing, testing, process audit, and performance of software. This paper discusses the consideration of return on investment (ROI) assessment criteria derived from the software and its users. These criteria indicate that the approach may support a rational consideration of all relevant criteria when evaluating software, and shows examples of actual return on investment models. Conducted an analysis of the assessment criteria that affect the return on investment if these criteria have a disproportionate effort that resulted in a return on investment of a software decreased. Index Terms - Assessment criteria, Quality assurance, Return on Investment, Software product


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