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Integrated reverse-diodes for GaN-HEMT structures

: Reiner, R.; Waltereit, P.; Weiss, B.; Wespel, M.; Quay, R.; Schlechtweg, M.; Mikulla, M.; Ambacher, O.


Institute of Electrical and Electronics Engineers -IEEE-; IEEE Electron Devices Society:
IEEE 27th International Symposium on Power Semiconductor Devices & IC's, ISPSD 2015. Proceedings : May 10-14, 2015; Kowloon Shangri-La, Hong Kong
Piscataway, NJ: IEEE, 2015
ISBN: 978-1-4799-6259-4 (Print)
ISBN: 978-1-4799-6261-7
International Symposium on Power Semiconductor Devices & IC's (ISPSD) <27, 2015, Hong Kong>
Conference Paper
Fraunhofer IAF ()
power transistors; gallium nitride; driver circuits; integrated circuits; HEMTs; dc-dc power converters

This work presents a quasi-normally-off gallium nitride (GaN) transistor with positive gate threshold voltage based on depletion-mode technology, suitable for gate drivers or logic circuits. Quasi-normally-off behaviour is achieved by the series connection of multiple Schottky diodes in the source path of an initially normally-on transistor. As opposed to conventional approaches, a novel quasi-normally-off gate driver circuit avoids the static shoot-through current path in the driver final stage and ensures a safe blocking state of a d-mode power switch in case of driver failure with only one negative driver supply voltage. For evaluation a hybrid integrated GaN power module is built, comprising a 2.4 A gate driver and 600 V/ 24 A boost converter switching cell. Measurements of pulsed inductive switching up to 274 V/ 12 A show gate voltage rise and fall times of 5.4 ns and 3.8 ns, boost converter switch node transition times as low as 1.6 ns and 1.2 ns, and maximum slew-rates up to 91 V/ns during turn-on transitions, and up to 177 V/ns during turn-off transitions, respectively.