scholarly journals Analysis and Suppression of Unwanted Turn-On and Parasitic Oscillation in SiC JFET-Based Bi-Directional Switches

Electronics ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 126 ◽  
Author(s):  
Lina Wang ◽  
Junyi Yang ◽  
Haobo Ma ◽  
Zeyuan Wang ◽  
Kabir Olanrewaju ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Matrix Converters ◽  
Turn On ◽  
High Efficient ◽  
Power Electronic Circuits ◽  
In Series ◽  
Ferrite Ring ◽  
Effect Transistor ◽  
Parasitic Oscillation ◽  
Selection Of

Silicon Carbide (SiC)-based Bi-Directional Switches (BDS) have great potential in the construction of several power electronic circuits including multi-level converters, solid-state breakers, matrix converters, HERIC (high efficient and reliable inverter concept) photovoltaic grid-connected inverters and so on. In this paper, two issues with the application of SiC-based BDSs, namely, unwanted turn-on and parasitic oscillation, are deeply investigated. To eliminate unwanted turn-on, it is proposed to add a capacitor (CX) paralleled at the signal input port of the driver IC (integrated circuit) and the capacitance range of CX is also analytically derived to guide the selection of CX. To mitigate parasitic oscillation, a combinational method, which combines a snubber capacitor (CJ) paralleled with the JFET (Junction Field Effect Transistor) and a ferrite ring connected in series with the power line, is proposed. It is verified that the use of CJ mainly improves the turn-off transient and the use of a ferrite ring damps the current oscillation during the turn-on transient significantly. The effects of the proposed methods have been demonstrated by theoretical analysis and verified by experimental results.

Preparation of TEM samples by focused ion beams

1995 ◽  
Vol 53 ◽  
pp. 518-519
Author(s):  
John F. Walker ◽  
J C Reiner ◽  
C Solenthaler
Keyword(s):  
Integrated Circuit ◽  
Polycrystalline Silicon ◽  
Field Effect Transistor ◽  
High Spatial Resolution ◽  
Ion Beam ◽  
Ion Beams ◽  
Focused Ion Beams ◽  
Precise Location ◽  
Effect Transistor ◽  
Circuit Technology

The high spatial resolution available from TEM can be used with great advantage in the field of microelectronics to identify problems associated with the continually shrinking geometries of integrated circuit technology. In many cases the location of the problem can be the most problematic element of sample preparation. Focused ion beams (FIB) have previously been used to prepare TEM specimens, but not including using the ion beam imaging capabilities to locate a buried feature of interest. Here we describe how a defect has been located using the ability of a FIB to both mill a section and to search for a defect whose precise location is unknown. The defect is known from electrical leakage measurements to be a break in the gate oxide of a field effect transistor. The gate is a square of polycrystalline silicon, approximately 1μm×1μm, on a silicon dioxide barrier which is about 17nm thick. The break in the oxide can occur anywhere within that square and is expected to be less than 100nm in diameter.

scholarly journals Modelling of Dynamic Properties of Silicon Carbide Junction Field-Effect Transistors (JFETs)

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 187 ◽  
Author(s):  
Kamil Bargieł ◽  
Damian Bisewski ◽  
Janusz Zarębski
Keyword(s):  
Silicon Carbide ◽  
Integrated Circuit ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Dynamic Properties ◽  
Modified Model ◽  
Spice Model ◽  
Capacitance Voltage ◽  
Effect Transistor ◽  
Switching Characteristics

The paper deals with the problem of modelling and analyzing the dynamic properties of a Junction Field Effect Transistor (JFET) made of silicon carbide. An examination of the usefulness of the built-in JFET Simulation Program with Integrated Circuit Emphasis (SPICE) model was performed. A modified model of silicon carbide JFET was proposed to increase modelling accuracy. An evaluation of the accuracy of the modified model was performed by comparison of the measured and calculated capacitance–voltage characteristics as well as the switching characteristics of JFETs.

scholarly journals Backside Chippings Improvement through Wafer Dicing Parameter Optimization and Understanding the Anistropic Silicon Properties

2021 ◽  
pp. 144-152
Author(s):  
Aiza Marie E. Agudon ◽  
Bryan Christian S. Bacquian
Keyword(s):  
Integrated Circuit ◽  
Electronic Devices ◽  
Silicon Wafers ◽  
Form Complex ◽  
Work Related ◽  
Front End ◽  
Wafer Thickness ◽  
Fully Automatic ◽  
Direct Materials ◽  
Selection Of

Semiconductor Companies and Industries soar high as the trend for electronic gadgets and devices increases. Transition from “manual” to “fully automatic” application is one of the advantages why consumer adapt to changes and prefer electronic devices as one of daily answers. Individuals who admire these electronic devices often ask how they are made. As we look inside each device, we can notice interconnected microchips commonly called IC (Integrated Circuit). These are specially prepared silicon wafers where integrated circuit are developed. Commonly, each device is composed of numerous microchips depending on the design and functionality IC production is processed from “front-end” to “back-end” assembly. Front-end assembly includes wafer fabrication where electrical circuitry is prepared and integrated to every single silicon wafers. Back-end assembly covers processing the wafer by cutting into smaller individual and independent components called “dice”. Each dice will be placed into Leadframe, bonded with wires prior encapsulating with mold compounds. After molding, each IC will be cut through a process called singulation. Afterwards, all molded units are subjected for functional testing. Dice is central to each IC; it is where miniature transistor, resistor and capacitor are integrated to form complex small circuitry in microchips. Pre-assembly (Pre-assy) stations have the first hand prior to all succeeding stations. Live wafers are primary direct materials processed in these stations. Robust work instruction and parameter must be practiced during handling and processing to avoid gross rejection and possible work-related defects. The paper is all about the challenges to resolve and improved the backside chippings in 280um wafer thickness in mechanical dicing saw. The conventional Mechanical dicing process induce a lot of mechanical stress and vibration during the cutting process which oftentimes lead to backside chipping and die crack issues. However, backside chippings can mitigate with proper selection of parameter settings and understand the silicon wafer properties.

scholarly journals Selection of sowing date and biofertilization as alternatives to improve the yield and profitability of the F68 rice variety

2020 ◽  
Vol 38 (1) ◽  
pp. 61-72
Author(s):  
Yeison Mauricio Quevedo-Amaya ◽  
José Isidro Beltrán-Medina ◽  
José Álvaro Hoyos-Cartagena ◽  
John Edinson Calderón-Carvajal ◽  
Eduardo Barragán-Quijano
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Carbon Balance ◽  
Sowing Date ◽  
Dry Matter Accumulation ◽  
Phosphate Solubilizing Bacteria ◽  
Area Index ◽  
Use Of Resources ◽  
High Efficient ◽  
Selection Of

Multiple factors influence rice yield. Developing management practices that increase crop yield and an efficient use of resources are challenging to modern agriculture. Consequently, the aim of this study was to evaluate biological nitrogen fixation and bacterial phosphorous solubilization (biofertilization) practices with the selection of the sowing date. Three sowing dates (May, July and August) were evaluated when interacting with two mineral nutrition treatments using a randomized complete block design in a split-plot arrangement. Leaf carbon balance, leaf area index, interception and radiation use efficiency, harvest index, dry matter accumulation, nutritional status, and yield were quantified. Results showed that the maximum yield was obtained in the sowing date of August. Additionally, yield increased by 18.92% with the biofertilization treatment, reaching 35.18% of profitability compared to the local production practice. High yields were related to a higher carbon balance during flowering, which was 11.56% and 54.04% higher in August than in July and May, respectively, due to a lower night temperature. In addition, a high efficient use of radiation, which in August was 17.56% and 41.23% higher than in July and May, respectively, contributed to obtain higher yields and this behavior is related to the selection of the sowing date. Likewise, a rapid development of the leaf area index and an optimum foliar nitrogen concentration (>3%) were observed. This allowed for greater efficient use of radiation and is attributed to the activity of nitrogen-fixing and phosphate solubilizing bacteria that also act as plant growth promoters.

Sputtered WSix for micromechanical structures

1995 ◽  
Vol 10 (7) ◽  
pp. 1710-1720 ◽  
Author(s):  
Muh-Ling Ger ◽  
Richard B. Brown
Keyword(s):  
Thin Films ◽  
Integrated Circuit ◽  
Elastic Moduli ◽  
Stress Measurement ◽  
Rutherford Backscattering Spectrometry ◽  
Thermal Coefficient ◽  
Deposition Pressure ◽  
Sputtered Films ◽  
Effect Transistor ◽  
Micromechanical Structures

Tungsten silicide (WSix) thin tilms have been investigated for use as integrated circuit interconnect and self-aligned MESFET (metal-semiconductor field-effect transistor) gates because of their low resistivity and thermal and chemical stability. These same characteristics make them interesting materials for prospective use in micromechanical structures. However, little information on residual stresses, elastic moduli, or other micromechanical properties has been available for refractory metal silicide thin films. This paper presents the morphology and stress characteristics of cosputtered WSix thin films, including crystal structure variations and orientation-dependent stresses, as a function of the deposition pressure. The compositions of WSix thin films were analyzed by Rutherford backscattering spectrometry (RBS). The biaxial elastic modulus and thermal coefficient of expansion were found for the sputtered films. Stress-measurement methods and annealing are discussed. Released diaphragms of different sizes and shapes, having controlled residual stress, have been fabricated.

Design of Full-bridge DC-DC Converter 311/100 V 1kW with PSPWM Method to Get ZVS Condition

2017 ◽  
Vol 8 (1) ◽  
pp. 59
Author(s):  
Toni Prasetya ◽  
F. Danang Wijaya ◽  
Eka Firmansyah
Keyword(s):  
Power Loss ◽  
Transition Process ◽  
Switching Frequency ◽  
Leakage Inductance ◽  
Zero Voltage Switching ◽  
Switching Power ◽  
Turn On ◽  
In Series ◽  
Zero Voltage ◽  
Primary Current

Enhancing the switching frequency can increase the power density of a fullbridge dc-dc converter. However, power loss in switches will increase due to the intersection of voltage and current during turn-on and turn-off transition process. The switching power loss can be reduced by making the condition of zero voltage switching (ZVS) which in this study is obtained by using the phase-shifted PWM method. Achieving this condition requires appropriate parameters such as deadtime, leakage inductance, and the primary current of transformer in sufficient value. In this study, ZVS is achieved when the transformer leakage inductance of 14.12 μH is added with external inductance of 24.29 μH which is installed in series with transformer and when the primary current of transformer is more than 1.289 A.

Application of the Combinatorial Inspection Method on the Buried Steel Pipelines in China

2006 ◽  
Author(s):  
Bing Liu ◽  
Renyang He ◽  
Hong Zhang ◽  
Jian Shuai
Keyword(s):  
Engineering Application ◽  
Proper Selection ◽  
Inspection Method ◽  
Know How ◽  
Direct Assessment ◽  
High Efficient ◽  
External Corrosion ◽  
Engineering Practices ◽  
Inspection Techniques ◽  
Selection Of

In general, the pipeline external corrosion direct assessment should be synchronously done by two or more inspection tools. Hence, it is very important to know how to develop the high-efficient and accurate combinatorial inspection techniques for engineering application. In this paper, the advantages, disadvantages and adaptabilities of the existing techniques and instruments are reviewed. Considering the technical difficulties in Chinese engineering practices, five different combinatorial inspection techniques were then brought forward. The proper selection of the combinational inspection technique can be determined by the inspection aim, servicing environment and type of the pipeline, soil, and so on. However, it should be noted that each combinatorial inspection technique can be used most of the time with some demerits. Engineering application showed that the proposed techniques can be directly and efficiently used to assess the pipeline external corrosion.

scholarly journals Sub–turn-on exciton quenching due to molecular orientation and polarization in organic light-emitting devices

2020 ◽  
Vol 6 (32) ◽  
pp. eabb2659
Author(s):  
John S. Bangsund ◽  
Jack R. Van Sambeek ◽  
Nolan M. Concannon ◽  
Russell J. Holmes
Keyword(s):  
Transport Layer ◽  
Electron Transport Layer ◽  
Intrinsic Polarization ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Turn On ◽  
Organic Light ◽  
Organic Light Emitting Devices ◽  
Lock In ◽  
Selection Of

The efficiency of organic light-emitting devices (OLEDs) is often limited by roll-off, where efficiency decreases with increasing bias. In most OLEDs, roll-off primarily occurs due to exciton quenching, which is commonly assumed to be active only above device turn-on. Below turn-on, exciton and charge carrier densities are often presumed to be too small to cause quenching. Using lock-in detection of photoluminescence, we find that this assumption is not generally valid; luminescence can be quenched by >20% at biases below turn-on. We show that this low-bias quenching is due to hole accumulation induced by intrinsic polarization of the electron transport layer (ETL). Further, we demonstrate that selection of nonpolar ETLs or heating during deposition minimizes these losses, leading to efficiency enhancements of >15%. These results reveal design rules to optimize efficiency, clarify how ultrastable glasses improve OLED performance, and demonstrate the importance of quantifying exciton quenching at low bias.

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