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Home > Thèses et HDR > PhD in 2023

20/03/2023 - Florian RIGAUD MINET

by Arnaud Lelevé, Laurent Krähenbühl - published on , updated on


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Florian RIGAUD MINET defended his PhD on March 20th, 2023 at 09:45AM.
Place : CHROME 1 room of la Maison MINATEC (3 Parv. Louis Néel, 38054 Grenoble)

Jury :
- Matteo MENEGHINI , Professeur à la Padova University
- Frédéric MORANCHO , Professeur au LAAS, Toulouse

- Natalie LABAT , Professeur à l’IMS à Bordeaux

- Dominique PLANSON , Professeur à AMPERE, directeur de thèse
- Hervé MOREL , Directeur de Recherche à AMPERE, co-encadrant
- Julien BUCKLEY , Docteur au CEA-LETI, co-encadrant

Abstract :
Nowadays the electrification of our society leads to a huge demand for technologies related to power conversion systems. Lateral Gallium Nitride (GaN) transistors made on silicon wafers were shown to be more adapted for high-efficiency power conversion over their silicon counterparts in the mid-voltage range (100 V–1000 V) at a reasonable cost. The targeted power converters are phone or laptop chargers, onboard chargers in electric vehicles, data center power supplies, micro-inverters for photovoltaics and more-electric aircraft power converters. Power transistor scaling may be interesting to improve converter efficiency. Indeed, it could on the one hand,
reduce the transistor-related charges QXX decreasing the switching time and hence the switching losses or on the other hand, decrease the on-state static resistance RDS,ON. However, the scaling should also result in a reduction of the device breakdown voltage as well as a switching that is more sensitive to parasitics that may have disturbed its stability/losses.
In this thesis, the electric field distribution management and the switching losses of lateral 650 V rated GaN-on-Silicon power devices built at CEA-LETI are studied. To do so, an electrical and physical failure analysis was performed to identify the voltage limitation of lateral GaN-on-Si diode test vehicles with different layouts and substrate connections. To study the electric field distribution by Technology Computer Assisted Design (TCAD) using Synopsys® SentaurusTM, the electric field variation should reproduce the experimental breakdown voltage. Thus, a buffer trap calibration method based on experimental protocols was initiated. Finally, a new hard switching characterization test bench was set up to study the transistor design and manufacturing process impact on the switching losses of lateral GaN-on-Si transistors. The results help to derive guidelines for the technology and design scaling of the future generations of fully recessed GaN-on-Si Metal Insulator Semiconductor High Electron Mobility Transistor (MIS-HEMT).

Keywords :
Power electronics, Power devices, GaN devices, HEMT, Breakdown voltage, TCAD, Hard switching

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