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Modelling of GaN Power Switches

Jogi, Sreeram
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1431717800

Abstract Details

2015, Master of Science, University of Toledo, Electrical Engineering.
.The main goal of this work was to develop the necessary expertise and model various parameters and characteristics of gallium nitride power HEMT (High Electron Mobility Transistor) devices. These include modelling of voltage-current characteristics, high temperature reverse bias leakage current, some circuit simulation, as well as radiation related effects on the device performance. Before modelling gallium nitride transistors, several other types of devices were modelled as part of a process to better understand the underlying physics involved in simulating HEMTs. To better compare the performance of commercially available gallium nitride transistors with the modelled gallium nitride devices, different types of depletion and enhancement structures of gallium nitride transistors were modelled. The voltage-current characteristics are simulated for various physically modelled gallium nitride structures. The obtained results are compared with those for commercially available gallium nitride transistors. Furthermore, drain to source leakage currents (at high temperature) of physically modelled gallium nitride devices were also modelled and are compared with performance of commercially available gallium nitride devices such as from Efficient Power Conversion Corporation (EPC®), including with actual measurements and test performed in our lab. The resulting simulations and experiments gave insight towards the factors which were limiting the device performance due to self-heating, leakage currents and the device geometry. We reviewed the electrical behavior of AlGaN/GaN HEMTs using circuit simulation tools. Basic power circuits were modelled in PSpice® (Circuit simulator from OrCAD Cadence) and Silvaco TCAD® (Process & Device simulator framework from Silvaco, Inc.), in order to observe switching behavior and compare the obtained results. To do this, commercially available EPC 2012 devices were imported into PSpice® and physically modelled enhancement gallium nitride HEMT devices were imported into MixedMode® (Circuit simulation module in Silvaco TCAD®). Additionally, experimental switching results are also discussed. The degree of immunity to single event effects such as heavy ion radiation is simulated and compared using ATLAS® (Device simulation module in Silvaco TCAD®). Also, an effect of long-term switching (latching) in both the off- and on-state, in unpackaged devices exposed to blue laser light, was experimentally observed in our lab. To understand this latching effect, in a simulated gallium nitride device, a layer of (trapped carrier) charge was assumed to form as a result of the irradiation. To model this behavior, a substantial amount of interface charge is added to the device and simulations were able to replicate the observed latching effect. This experiment demonstrates that trap-related light absorption and charge carrier generation plays a major role in the device performance.
Daniel Georgiev, Dr. (Committee Chair)
Vijay Devabhaktuni, Dr. (Committee Member)
Roger King, Dr. (Committee Member)
94 p.
Electrical Engineering
AlGaN-GaN Modelling; Silvaco Atlas; HEMT

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Citations

  • Jogi, S. (2015). Modelling of GaN Power Switches [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1431717800

    APA Style (7th edition)

  • Jogi, Sreeram. Modelling of GaN Power Switches. 2015. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1431717800.

    MLA Style (8th edition)

  • Jogi, Sreeram. "Modelling of GaN Power Switches." Master's thesis, University of Toledo, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1431717800

    Chicago Manual of Style (17th edition)

toledo1431717800
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© 2015, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.