1. All-GaN-Integrated Cascode Heterojunction Field Effect Transistors.
- Author
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Jiang, Sheng, Lee, Kean Boon, Guiney, Ivor, Miaja, Pablo F., Zaidi, Zaffar H., Qian, Hongtu, Wallis, David J., Forsyth, Andrew J., Humphreys, Colin J., and Houston, Peter A.
- Subjects
ELECTRIC properties of gallium nitride ,CASCADE converters ,HETEROJUNCTION field effect transistors ,ELECTRIC switchgear ,METAL oxide semiconductor field-effect transistors - Abstract
All-GaN-integrated cascode heterojunction field effect transistors were designed and fabricated for power switching applications. A threshold voltage of +2 V was achieved using a fluorine treatment and a metal–insulator–semiconductor gate structure on the enhancement mode part. The cascode device exhibited an output current of 300 mA/mm by matching the current drivability of both enhancement and depletion mode parts. The optimization was achieved by shifting the threshold voltage of the depletion mode section to a more negative value with the addition of a dielectric layer under the gate. The switching performance of the cascode was compared to the equivalent GaN enhancement-mode-only device by measuring the hard switching speed at 200 V under an inductive load in a double pulse tester. For the first time, we demonstrate the switching speed advantage of the cascode over equivalent GaN enhancement-mode-only devices, due to the reduced Miller-effect and the unique switching mechanisms. These observations suggest that practical power switches at high power and high switching frequency will benefit as part of an integrated cascode configuration. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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