Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781720402664
Category :
Languages : en
Pages : 70
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Book Description
Gallium nitride (GaN) is a most promising wide band-gap semiconductor for use in high-power microwave devices. It has functioned at 320 C, and higher values are well within theoretical limits. By combining four devices, 20 W has been developed at X-band. GaN High Electron Mobility Transistors (HEMTs) are unique in that the two-dimensional electron gas (2DEG) is supported not by intentional doping, but instead by polarization charge developed at the interface between the bulk GaN region and the AlGaN epitaxial layer. The polarization charge is composed of two parts: spontaneous and piezoelectric. This behavior is unlike other semiconductors, and for that reason, no commercially available modeling software exists. The theme of this document is to develop a self-consistent approach to developing the pertinent equations to be solved. A Space Act Agreement, "Effects in AlGaN/GaN HEMT Semiconductors" with Silvaco Data Systems to implement this approach into their existing software for III-V semiconductors, is in place (summer of 2002).Freeman, Jon C.Glenn Research CenterGALLIUM NITRIDES; FIELD EFFECT TRANSISTORS; HIGH ELECTRON MOBILITY TRANSISTORS; ENERGY GAPS (SOLID STATE); MICROWAVE EQUIPMENT; POLARIZATION (CHARGE SEPARATION); PIEZOELECTRICITY
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
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Author:
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Category :
Languages : en
Pages :
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Author: Jon C. Freeman
Publisher:
ISBN:
Category :
Languages : en
Pages : 65
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Author:
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ISBN:
Category :
Languages : en
Pages :
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Author: Jaime Alberto Zamudio Flores
Publisher: kassel university press GmbH
ISBN: 3862193640
Category : Gallium nitride
Languages : en
Pages : 257
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Book Description
This work presents a comprehensive modeling strategy for advanced large-size AlGaN/GaN HEMTs. A 22-element equivalent circuit with 12 extrinsic elements, including 6 capacitances, serves as small-signal model and as basis for a large-signal model. ANalysis of such capacitances leads to original equations, employed to form capacitance ratios. BAsic assumptions of existing parameter extractions for 22-element equivalent circuits are perfected: A) Required capacitance ratios are evaluated with device's top-view images. B) Influences of field plates and source air-bridges on these ratios are considered. The large-signal model contains a gate charge's non-quasi-static model and a dispersive-IDS model. THe extrinsic-to-intrinsic voltage transformation needed to calculate non-quasi-static parameters from small-signal parameters is improved with a new description for the measurement's boundary bias points. ALl IDS-model parameters, including time constants of charge-trapping and self-heating, are extracted using pulsed-DC IV and IDS-transient measurements, highlighting the modeling strategy's empirical character.
Author: Ujwal Radhakrishna
Publisher:
ISBN:
Category :
Languages : en
Pages : 84
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Book Description
Gallium Nitride (GaN)-based high electron mobility transistors (HEMTs) are rapidly emerging as front-runners in high-power mm-wave circuit applications. For circuit design with current devices and to allow sensible future performance projections from device engineering in such a rapidly evolving technology, compact device models are essential. In this thesis, a physics-based compact model is developed for short channel GaN HEMTs. The model is based on the concept of virtual source (VS) transport originally developed for scaled silicon field effect transistors. Self-consistent current and charge expressions in the model require very few parameters. The parameters have straightforward physical meanings and can be extracted through independent measurements. The model is implemented in Verilog-A and is compatible with state of the art circuit simulators. The new model is calibrated and validated with experimental DC I-V and S-parameter measurements of fabricated devices. Using the model, a projection of cut-off frequency (f-[tau]) of GaN-based HEMTs with scaling is performed to highlight performance bottlenecks.
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Category :
Languages : en
Pages : 54
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Author: Alex Lidow
Publisher: John Wiley & Sons
ISBN: 1118844769
Category : Science
Languages : en
Pages : 266
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Book Description
Gallium nitride (GaN) is an emerging technology that promises to displace silicon MOSFETs in the next generation of power transistors. As silicon approaches its performance limits, GaN devices offer superior conductivity and switching characteristics, allowing designers to greatly reduce system power losses, size, weight, and cost. This timely second edition has been substantially expanded to keep students and practicing power conversion engineers ahead of the learning curve in GaN technology advancements. Acknowledging that GaN transistors are not one-to-one replacements for the current MOSFET technology, this book serves as a practical guide for understanding basic GaN transistor construction, characteristics, and applications. Included are discussions on the fundamental physics of these power semiconductors, layout and other circuit design considerations, as well as specific application examples demonstrating design techniques when employing GaN devices. With higher-frequency switching capabilities, GaN devices offer the chance to increase efficiency in existing applications such as DC–DC conversion, while opening possibilities for new applications including wireless power transfer and envelope tracking. This book is an essential learning tool and reference guide to enable power conversion engineers to design energy-efficient, smaller and more cost-effective products using GaN transistors. Key features: Written by leaders in the power semiconductor field and industry pioneers in GaN power transistor technology and applications. Contains useful discussions on device–circuit interactions, which are highly valuable since the new and high performance GaN power transistors require thoughtfully designed drive/control circuits in order to fully achieve their performance potential. Features practical guidance on formulating specific circuit designs when constructing power conversion systems using GaN transistors – see companion website for further details. A valuable learning resource for professional engineers and systems designers needing to fully understand new devices as well as electrical engineering students.
Author: Peng Luo
Publisher: Cuvillier Verlag
ISBN: 3736989067
Category : Technology & Engineering
Languages : en
Pages : 160
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Book Description
GaN HEMTs are regarded as one of the most promising RF power transistor technologies thanks to their high-voltage high-speed characteristics. However, they are still known to be prone to trapping effects, which hamper achievable output power and linearity. Hence, accurately and efficiently modeling the trapping effects is crucial in nonlinear large-signal modeling for GaN HEMTs. This work proposes a trap model based on Chalmers model, an industry standard large-signal model. Instead of a complex nonlinear trap description, only four constant parameters of the proposed trap model need to be determined to accurately describe the significant impacts of the trapping effects, e.g., drain-source current slump, typical kink observed in pulsed I/V characteristics, and degradation of the output power. Moreover, the extraction procedure of the trap model parameters is based on pulsed S-parameter measurements, which allow to freeze traps and isolate the trapping effects from self-heating. The model validity is tested through small- and large-signal model verification procedures. Particularly, it is shown that the use of this trap model enables to dramatically improve the large-signal simulation results.
