Design And Fabrication Of Nitride Based High Power Devices

1997 ◽  
Vol 483 ◽  
Author(s):  
Z. Z. Bandić ◽  
E.C. Piquette ◽  
P.M. Bridger ◽  
T.F. Kuech ◽  
T. C. Mcgill
Keyword(s):  
Critical Field ◽  
High Power ◽  
Minority Carrier ◽  
Planar Geometry ◽  
Model Parameters ◽  
Recombination Lifetime ◽  
Thyristor Switch ◽  
And Performance ◽  
Schottky Devices ◽  
Recombination Lifetimes

AbstractWe modeled the breakdown voltage, critical current density and maximum operating frequency of several GaN and GaN/AlN based high power and high temperature electronic devices. Important model parameters which influence device design and performance are minority carrier recombination lifetime and critical field for electric breakdown.GaN Schottky devices have been fabricated in the planar geometry. Current-voltage measurements indicated the importance of the vertical geometry for achieving large breakdown voltages. The minority carrier (hole) recombination lifetimes have been measured by electron beam induced currents (EBIC). The measured hole lifetime of 7 ns and estimate for the critical field indicate the possibility of GaN/AlGaN thyristor switch devices operating at 5KV with current densities approximately equal to 200 A/cm2 and at frequencies above 2MHz.The GaN structural and optical materials quality and processing requirement for etching is discussed.

Nitride Based High Power Devices: Transport Properties, Linear Defects And Goals

1998 ◽  
Vol 512 ◽  
Author(s):  
Z. Z. Bandić ◽  
P. M. Bridger ◽  
E. C. Piquette ◽  
R. A. Beach ◽  
V. M. Phanse ◽  
...  
Keyword(s):  
Transport Properties ◽  
Critical Field ◽  
High Power ◽  
Minority Carrier Lifetime ◽  
Electric Breakdown ◽  
Power Devices ◽  
Critical Fields ◽  
Linear Defects ◽  
Bandgap Semiconductors ◽  
Recombination Lifetimes

ABSTRACTThe wide bandgap semiconductors GaN and AlGaN show promise for high voltage standoff layers in high power devices such as GaN Schottky rectifiers and GaN/AlGaN thyristorlike switches. The material properties which significantly influence the device design and performance are electron and hole diffusion lengths, recombination lifetimes and the critical field for electric breakdown. We have fabricated high standoff voltage (> 450 V) GaN Schot-tky rectifiers, and measured a lower limit for the critical field for electric breakdown to be (2 ± 0.5) · 106 V/cm. Diffusion lengths and recombination lifetimes were measured by electron beam induced current on unintentionally doped, n and p-type GaN samples grown by various epitaxial techniques. To establish the possible effects of linear dislocations and other defects on the transport and breakdown properties, the same sample surfaces were analyzed by AFM. On some of the samples, our measurements indicate that the dislocations appear to be electrically active and that recombination at dislocations occupying grain boundaries limit the minority carrier lifetime to the nanosecond range. Based on the measurements of transport properties, critical fields and the modeling of the devices proposed, our estimates indicate that DARPA/EPRI goals for megawatt electronics set at 5 kV standoff voltage and 200 A on-state current might be achieved with 15 – 20 μm thick layers grown by HVPE, at approximately 1. 1016 cm−3 doping levels, and 1 – 2cm2 device active area.

Correlation of Fe-Rich Defect Centre and Minority Carrier Lifetime in p-Type Multicrystalline Silicon

2013 ◽  
Vol 440 ◽  
pp. 82-87 ◽  
Author(s):  
Mohammad Jahangir Alam ◽  
Mohammad Ziaur Rahman
Keyword(s):  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Multicrystalline Silicon ◽  
Recombination Lifetime ◽  
Spatially Resolved ◽  
Carrier Recombination ◽  
Negative Role ◽  
P Type ◽  
The Impact

A comparative study has been made to analyze the impact of interstitial iron in minority carrier lifetime of multicrystalline silicon (mc-Si). It is shown that iron plays a negative role and is considered very detrimental for minority carrier recombination lifetime. The analytical results of this study are aligned with the spatially resolved imaging analysis of iron rich mc-Si.

Review and performance of four models to assess the fate of radionuclides and heavy metals in surface soil

1997 ◽  
Vol 77 (3) ◽  
pp. 333-344 ◽  
Author(s):  
M. I. Sheppard ◽  
D. E. Elrick ◽  
S. R. Peterson
Keyword(s):  
Environmental Impact ◽  
Waste Management ◽  
Chemical Exchange ◽  
Nuclear Industry ◽  
Hydrodynamic Dispersion ◽  
Model Parameters ◽  
Validation Data ◽  
Soil Transport ◽  
And Performance ◽  
The Impact

The nuclear industry uses computer models to calculate and assess the impact of its present and future releases to the environment, both from operating reactors and from existing licensed and planned waste management facilities. We review four soil models varying in complexity that could be useful for environmental impact assessment. The goal of this comparison is to direct the combined use of these models in order to preserve simplicity, yet increase the rigor of Canadian environmental assessment calculations involving soil transport pathways. The four models chosen are: the Soil Chemical Exchange and Migration of Radionuclides (SCEMR1) model; the Baes and Sharp/Preclosure PREAC soil model, both used in Canada's nuclear fuel waste management program; the Convection-Dispersion Equation (CDE) model, commonly used in contaminant transport applications; and the Canadian Standards Association (CSA) derived release limit model used for normal operations at nuclear facilities. We discuss how each model operates, its timestep and depth increment options and the limitations of each of the models. Major model assumptions are discussed and the performance of these models is compared quantitatively for a scenario involving surface deposition or irrigation. A sensitivity analysis of the CDE model illustrates the influence of the important model parameters: the amount of infiltrating water, V; the hydrodynamic dispersion coefficient, D; and the soil retention or partition coefficient, Kd. The important parameters in the other models are also identified. This work shows we need tested, robust, mechanistic unsaturated soil models with easily understood and measurable inputs, including data for the sensitive or important model parameters for Canada's priority contaminants. Soil scientists need to assist industry and its regulators by recommending a selection of models and supporting them with the provision of validation data to ensure high-quality environmental risk assessments are carried out in Canada. Key words: Soil transport models, environmental impact assessments, model structure, complexity and performance, radionuclides 137Cs, 90Sr, 129I

Development and performance test of a new high power RF window in S-band PLS-II LINAC

2017 ◽  
Vol 71 (11) ◽  
pp. 802-806
Author(s):  
Woon-Ha Hwang ◽  
Young-Do Joo ◽  
Seung-Hwan Kim ◽  
Jae-Young Choi ◽  
Sung-Ju Noh ◽  
...  
Keyword(s):  
High Power ◽  
Performance Test ◽  
Rf Window ◽  
And Performance

scholarly journals Development of wireless vertical bar spinner combat robot

2020 ◽  
Vol 18 (2) ◽  
pp. 759
Author(s):  
Amirul Syafiq Sadun ◽  
Jamaludin Jalani ◽  
Suziana Ahmad ◽  
Amiera Saryati Sadun ◽  
Sumaiya Mashori
Keyword(s):  
High Power ◽  
Vertical Axis ◽  
Horizontal Axis ◽  
Robot Design ◽  
Performance Requirement ◽  
Science Centre ◽  
National Science ◽  
And Performance

Recently, combat robot competition has become one of the most famous engineering competitions among schools and universities. The robots are usually built with a destructive weapon, which can immobilize or disable opponent’s robot and win the match. Despite the variety of robot design and concept, the trend has shown that most of the local contestant tend to design a horizontal axis weapon type. In this project, a wireless vertical axis bar spinner combat robot is designed and developed for the 3rd Malaysia Combat Robot Competition which was held at National Science Centre (PSN) in 2017. The robot is controlled using radio control (RC) and powered by a highly discharge 22.2V Lithium Polymer (LiPo) chemical battery. Furthermore, related analysis has been conducted to meet the design and performance requirement of the competition. With the DC brush motor and thick metal bar rotating in vertical axis, the robot has proven to produce high power, torque and speed during the competition.

Characteristics and performance of high-power CW krypton arc lamps for Nd:YAG laser pumping

1971 ◽  
Vol 7 (6) ◽  
pp. 300-300
Author(s):  
W. Koechner ◽  
L. DeBenedictis ◽  
E. Matovich ◽  
G. Mevers
Keyword(s):  
High Power ◽  
Nd:Yag Laser ◽  
Laser Pumping ◽  
And Performance

Design and performance of a high power pulsed magnetron

1957 ◽  
Vol 4 (2) ◽  
pp. 161-171 ◽  
Author(s):  
E.C. Okress ◽  
C.H. Gleason ◽  
R.A. White ◽  
W.R. Hayter
Keyword(s):  
High Power ◽  
And Performance ◽  
Pulsed Magnetron
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