“Leaky Dielectric” Model for the Suppression of Dynamic RON in Carbon Doped AlGaN/GaN HEMTs

Michael Uren, Serge Karboyan, Indranil Chatterjee, Alexander Pooth, Peter Moens, Abhishek Banerjee, Martin Kuball

Research output: Contribution to journalArticle (Academic Journal)

64 Citations (Scopus)
267 Downloads (Pure)

Abstract

GaN-on-Si power switching transistors that use carbon doped epitaxy are highly vulnerable to dynamic RON dispersion, leading to reduced switching efficiency. In this paper we identify the causes of this dispersion, using substrate bias ramps to isolate the leakage paths and trapping locations in the epitaxy, and simulation to identify their impact on the device characteristics. It is shown that leakage can occur both vertically and laterally and we suggest that this is associated not only with bulk transport, but also extended defects as well as hole gases at heterojunctions. For exactly the same epitaxial design it is shown using a “leaky dielectric” model that depending on the leakage paths, dynamic RON dispersion can vary between insignificant and infinite. An optimum leakage configuration is identified to minimize dispersion requiring a resistivity which increases with depth in the buffer stack. It is demonstrated that leakage through the undoped GaN channel is required over the entire gate to drain gap, and not just under the contacts, in order to fully suppress dispersion.
Original languageEnglish
Pages (from-to)2826-2834
Number of pages9
JournalIEEE Transactions on Electron Devices
Volume64
Issue number7
Early online date6 Jun 2017
DOIs
Publication statusPublished - Jul 2017

Structured keywords

  • CDTR

Keywords

  • Power electronics
  • current collapse
  • dynamic RON

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