Omar Chihani has defended his thesis on degradation of AlGaN/GaN HEMTs off the shelf components

On Thursday, September 27th 2018, Omar Chihani has defended his thesis. Awarded by the University of Bordeaux, his work was supervised by both IMS Bordeaux (CNRS/Bordeaux University/INP Bordeaux Aquitaine) and IRT Saint Exupéry. The high quality and the relevance of Omar’s thesis contributed to get significant results as a part of ROBUSTESSE project.


” Etude de la fiabilité de composants GaN en conversion d’énergie”

About his thesis

Space and transport industries are facing a strong global economic competition which is setting economic constraints on the cost of the functions. In order to reduce development costs and to propose new features more quickly, using components of the shelf (COTS) is very suitable. This work investigates the degradation of AlGaN/GaN HEMTs COTS submitted to HTRB lifetest. Steps in terms of temperature and voltage were performed in order to distinguish the effect of each stressor. The main aim is to establish a lifetime model, taking into account several degradation mechanisms, over a large range of temperatures and voltages. The experiments indicate the activation of different failure mechanisms during the stresses depending on the different ranges. The experimental analysis has been performed in order to characterize and verify when multiple failure mechanisms can be activated on such components and on which range these mechanisms may superpose.


A Study into Off The Shelf Components (COTS) technologies’ reliability Under operating environment conditions for the transport industry.


  • Mme Nathalie LABAT – IMS Laboratory – President of the jury
  • M. Frédéric MORANCHO – LAAS CNRS – Rapporteur
  • M. Dominique PLANSON – INSA Lyon – Rapporteur
  • Mme Mounira BERKANI – SATIE – Examiner
  • Mme Karine ISOIRD – LAAS CNRS – Examiner
  • M. Alain BENSOUSSAN – IRT Saint Exupéry – Examiner
  • M. Fabio COCCETTI – IRT Saint Exupéry – Invited
  • M. Stéphane AZZOPARDI – Safran Tech – Invited
  • M. Eric WOIRGARD – IMS Laboratory – PhD Advisor
  • M. Loïc THEOLIER – IMS Laboratory – PhD Advisor

O. Chihani, L. Theolier, A. Bensoussan, J-Y Deletage, A. Durier, E. Woirgard : “Temperature and voltage effects on HTRB and HTGB stresses for AlGaN/GaN HEMTs”. 2018

Omar Chihani has defended his thesis on degradation of AlGaN/GaN HEMTs off the shelf components
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