Simulation and characterization of electronic transport in AlGaN / GaN power transistors

Published : 11 June 2019

The AlGaN / GaN components currently developed at LETI are high voltage components (> 650V) with low on-state resistances for driving high currents (from the tens to the hundreds of amps). These components particularly address the market of power converters currently in full expansion (electric vehicles, renewable energies including solar, smart grids, etc.).

The preliminary work carried out at CEA-LETI allowed to determine the main phenomena limiting the transport of electrons in the accesses of the HEMT (High Electron Mobility Transistor) transistors but also under the MIS (Metal-Insulator-Semiconductor) gate of these transistors. It is now necessary to precisely define the transport properties of GaN material in case of low and high electric fields (necessary for GaN power but also for GaN RF) and to model this electronic transport in order to identify ways of improving performance. electrical devices.

The PhD student will be required to perform the following tasks: Electrical characterization (consolidation of the mobility measurement protocol, measurements of mobility as a function of charge and temperature, mobility spectroscopy measurements), simulation and modeling (simulation of the low-field and high-field mobility in the electron 2D gas formed at the AlGaN/GaN heterojunction and under the transistor gate: carrier scattering probability and electron transport with the Boltzmann equation or the non-equilibrium Greeen functions (NEGF) quantum formalism, development of analytical models of mobility, proposals for improvement of device performance.

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