PhD Position MSCA COFUND BEST: \"Hybrid PVD/ALD Multilayer Thin Film Deposition to Enhance Dielectric Breakdown Strength of Future High Voltage Electronic Devices for Sustainable Aeronautics\"

Organisation/Company University of Toulouse Department LAPLACE Institute Research Field Engineering > Materials engineering Engineering > Electrical engineering Chemistry > Inorganic chemistry Technology > Materials technology Researcher Profile First Stage Researcher (R1) Positions PhD Positions Application Deadline 23 Nov 2026
- 12:00 (Europe/Paris) Country France Type of Contract Temporary Job Status Full-time Hours Per Week 35 Offer Starting Date 1 Sep 2027 Is the job funded through the EU Research Framework Programme? Horizon Europe – COFUND Marie Curie Grant Agreement Number 101261439 Is the Job related to staff position within a Research Infrastructure? No

Offer Description

Faced with the urgent challenges of climate change and the need to drastically reduce global CO2 emissions, the electrification of transport has emerged as a key lever for reducing reliance on fossil fuels [1-3]. With 13.9% of transport emissions, aviation is the second biggest source of greenhouse gas emissions in the transport sector after road transport [4], and air-traffic is going to continue to rise over the next decades [5]. Against this backdrop, the aviation industry is reinventing itself around the concepts of the “More Electric Aircraft” (MEA) and, in the longer term, “All Electric Aircraft” (AEA). Historically, the sector has transitioned from onboard network voltages of 14/28 V DC to 115 V AC (400 Hz) networks, and subsequently—on the most recent long-range aircraft programs—to 270 V DC [6]. Ongoing studies are now exploring 800 V DC architectures for power electric propulsion systems ranging from a few hundred kilowatts to the megawatt level [7]. In the longer term beyond 2050, aeronautic aims to move beyond the megawatt range, with onboard voltage levels expected to range 1,000 V to 3,000 V DC [7]. This evolution presents new challenges regarding electrical insulation for onboard AC/DC high-power density conversion systems. Wide-bandgap power semiconductors (GaN, SiC) are central to these issues. Thanks to their high switching speeds and ability to withstand electric fields exceeding 3 MV/cm, they now enable the design of double-side cooling inverters with higher power density (50-100 kW/L) capable of operating at voltages up to 800 V nowadays [8, 9], and above 1 kV in the future. However, to operate safely and reliably, the top surface of semiconductor devices, as well as any critical metal part in the device package, must be appropriately insulated with high dielectric strength materials to separate high-voltage contacts from ground contacts, and using a compatible technological process. Thin metal oxides (SiO2, Al2O3, HfO2 …) or silicon (oxy)nitrides (SiN x , SiO x N y ) are traditional thin film dielectrics —namely surface passivants— for electronic devices and are typically deposited by thermal growth (few~10 nm) complemented by chemical vapor deposition (CVD) (few~100 nm) [10, 11]. While they exhibit good short term dielectric breakdown strength ( EBD ) with values ranging between 3-10 MV/cm, they are still suffering of long term high-field reliability issues [12], that will make critical the emergence of the next generation of high-voltage power devices. The reason is usually related to the introduction of defects (pinholes) within the films during the deposition process that lead to high leakage currents from electric field of only a few~MV/cm [13, 14], and actas nuclei location for irreversible electrical degradation processes [15]. Therefore, reinforcing inorganic films by engineering them with advanced deposition processes to reach an initial dielectric breakdown strength and eradicating any leakage current will enable to delay the early degradation processes and to considerably improve the long term high-field reliability of electronic devices, participating to the adoption of higher voltage converters in aeronautics.

Physical vapor deposition (PVD), particularly reactive magnetron sputtering, is a well-suited alternative to grow thick dielectric coatings. As a precursor-free process, it avoids carbon-, hydrogen
- and hydroxyl-containing residues associated with CVD chemistries that can promote charge trapping and leakage [13]. It is above all fast: deposition rates of tens of nm/min at low substrate temperature deliver micrometer-thick coatings in minutes. At the University of Nottingham (UK), PVD-grown AlN films (~15–150 nm) have already demonstrated EBD>15MV/cm together with high thermal conductivity of λ ~ 300 W/m·K [16]. The limitation arises at greater thickness. Sputtered films typically develop a columnar microstructure in which grain boundaries, pinholes, and aligned defects can form continuous leakage pathways through the dielectric, reducing EBD down to ~1–5 MV/cm. Multilayering partially addresses this problem: chemically distinct interfaces force re-nucleation, interrupt columnar boundaries, and hinder charge t