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International audience; A B S T R A C THeterojunction Bipolar Transistors needed for high-frequency applications require precise dopant control. Insitu doped epitaxies used during device fabrication rely on surface preparation to obtain an optimized dopingprofile. Defects due to imperfect cleaning relates to high emitter resistance and low-frequency noise.Base epitaxy is followed by the fabrication of thin L-shaped oxide spacers and in-situ arsenic-doped emitterepitaxy by Low Pressure Chemical Vapor Deposition. A cleaning step between spacers formation and emitterepitaxy is mandatory to remove residual contamination. Hydrofluoric acid (HF) wet cleaning, in-situ remoteplasma cleaning (SiconiTM) and thermal treatments have been tested. A minimum etching budget is sought forlimiting spacer consumption while adequately cleaning the interface.Time Of Flight-Secondary Ion Mass Spectroscopy (TOF-SIMS) and High-Resolution Transmission ElectronMicroscopy (HR-TEM) are used to characterize the interface and measure levels of arsenic, oxygen, fluorineand carbon. Emitter resistance and base-emitter breakdown voltage measurements are used to show the impacton electrical figures of merit. Siconi targeting 10 Å of thermal oxide removal followed by a thermal treatment(800 ◦C, 60 s) in the deposition chamber results the best process among the tested ones.

International audience; In this work, we propose to study and design a coil used to magnetize, by means of a Pulsed Field Magnetization (PFM) process, an inductor of a radial flux superconducting machine with one pair of poles. Each pole contains four similar HTS bulks of 30 mm diameter arranged in a square pattern. The cryostat already exists for this application and the temperature of the HTS bulks can vary from 4.2 K to their critical temperature, in transient state. For a given primary source of energy, here a capacitor bank of 10 kJ (5 mF, 2 kV) is available, the PFM process depends strongly on the value of the coil inductance used to generate pulsed field, because it defines the waveform of the current: peak value and time constant. Thus, 3D modeling of the coil is required in order to be sure that its inductance and the magnetic field produced will provide a full magnetization of HTS bulks. From the practical point of view, we would like to achieve an average magnetization of each pole around 3 T. In this paper, numerical modeling of coils with different number of turns coupled with circuit's equations is achieved. The maximum magnetic field obtained on the HTS bulks and estimated magnetization at the top center of each HTS bulk, are presented and discussed.