As part of the electronic PEPR "FRENCHDIAM" bringing together 8 leading academic entities (France 2030), the FRENCHDIAM project aims to develop a new generation of power components based on a diamond semiconductor, with unique features and performances. Advanced power electronics technologies are at the heart of the next generation of energy systems. Silicon is a well-established semiconductor material that has met the requirements of energy conversion for more than 50 years. However, it is widely recognized that a real improvement in power electronics will be obtained by employing devices based on wide bandgap semiconductor materials. Wide bandgap semiconductor materials have superior electrical characteristics to silicon for power devices. Power electronic devices based on wide bandgap semiconductors will significantly improve the performance of power electronic systems by offering higher blocking voltages, increased efficiency and reliability (higher performance-to-cost ratio), and reduced thermal requirements, leading to more efficient green electronic systems. Among these materials, diamond, classified as an ultra-wide bandgap material due to its very large bandgap energy (5.5 eV), is considered the ultimate semiconductor for power electronics applications due to its exceptional properties. Its dielectric strength is 3 times higher than that of silicon carbide (SiC) or gallium nitride (GaN) and more than 30 times better than that of silicon (Si), while the specific on-resistance is inversely proportional to the cube of this parameter. In addition, the carrier mobility is very high for both types of carriers and the thermal conductivity is unmatched.

The scientific objectives of this position are summarized in two main tasks: design diamond power devices, and characterize them in high voltage switching regime.
Design of diamond power devices
In close collaboration with the project consortium, the different devices will be studied using 1D and 2D finite element analyses (e.g. TCAD Sentaurus, Silvaco). Numerical analyses will evaluate the trade-offs between electrical performances (on-resistance, threshold voltage, transconductance and breakdown voltage), manufacturing parameters (diamond layer thickness and doping levels, oxide type and thickness, lithography and manufacturing steps) and geometrical parameters (e.g. gate length, gate-to-drain and gate-to-source distances, critical dimensions and safety margins). Particular attention will be paid to parasitic capacitors in order to assess as early as possible the switching performances and the best trade-offs between component parameters, conduction and switching losses. The different architectures will be evaluated in terms of electrical performance (on-state resistance, off-state electric fields) and manufacturing complexity (number of manufacturing processes and tolerance to dispersions). The best architectures will be designed (mask layout), in close collaboration with the consortium's French partners.
Switching regime characterization
Based on the test cards already produced in the laboratory, it will be necessary to support the test campaigns to measure the large-signal switching characteristics of the diamond transistors. Prior validation on commercial components will be necessary in order to validate and develop the test cards (e.g. double-pulse technique on inductive load). The reports will have to be written and shared within the consortium, and the results communicated through scientific publications.

This position is funded by a French collaborative research project PEPR electronics "FRENCHDIAM": The French diamond industry for power electronics. This project began in May 2024, for a period of 48 months, coordinated by LAAS (Toulouse), the Néel Institute (Grenoble) and the CEA (Grenoble+Toulouse). This postdoctoral researcher position is funded for 18 months.

Laplace (Plasma and Energy Conversion Laboratory) is a UMR supervised by the CNRS, INP-Toulouse and UPS. The laboratory has more than 300 people and represents the highest concentration of research in electrical engineering and Plasma in France. In particular, it is the only one to cover the "Plasma/materials/systems" continuum in an integrated manner. The CS group is composed of 35 full-time equivalents, and the main investigations focus on original concepts of associations of nested, superimposed and/or magnetically coupled switching cells in parallel, giving rise to complex circuits with often very branched topology. The research and technologies thus developed address both new energy management functionalities and high-performance applications in terms of waveform quality, compact filtering and three-dimensional integration with high specific power.