Impact Ionization in AlGaN/GaN HEMTs with InGaN back-barrier

Nicole Killat1,*, Milan Ťapajna1, Mustapha Faqir1, Tomas Palacios2, and Martin Kuball1
1Center for Device Thermography and Reliability (CDTR), H.H. Wills Physics Laboratory, University of Bristol,
Tyndall Avenue, Bristol BS8 1TL, United Kingdom
*E-Mail: Nicole.Killat@bristol.ac.uk, Phone: +44 117 9288750
2 Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

Keywords: HEMT, impact ionization, electroluminescence, InGaN back-barrier

Abstract

Electroluminescence (EL) spectroscopy in combination with capacitance-voltage (C-V) measurements and drift-diffusion simulations is presented as a novel methodology to study impact ionization in GaN-based devices, potentially benefiting industrial testing procedures. The EL spectrum of AlGaN/GaN HEMTs with InGaN back-barrier revealed hole generation in the InGaN layer due to impact ionization, which was supported by electron density simulations and temperature-dependent EL spectroscopy. C-V characteristics showed localized electron trapping in the InGaN barrier influencing the depletion behavior of the devices used.

Paper 10b.5.pdf