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De l'étude en bruit basse fréquence à la conception d'un oscillateur en bande-X à partir de transistors AlGaN/GaN HEMT

Abstract : This work is dedicated to the study in the field of low frequency noise characterization of Gallium Nitride High Electron Mobility Transistors (HEMT) and to the design of an X-Band low phase noise oscillator. First of all, we describe the Gallium Nitride intrinsic properties, the HEMT structure and the associated noise sources that can occur in such device. The low frequency noise (LFN) measurement methodology is also presented. Then, a comparative study is exposed using low frequency noise measurement between devices grown on different substrate (Si, SiC, Al2O3). Finally, an investigation on the 1/fg noise and the frequency index g is performed, indicating a correlation between the frequency index g and the transport mechanism of the carriers in the two dimensional electron gas (2DEG) or in a parasitic AlGaN channel between drain and gate. This study makes use of both LFN measurements and physical simulations. The second part focuses on HEMT grown on SiC substrate: low frequency noise spectra are investigated, and a mathematical extraction procedure is presented. Then, an accurate study is lade thanks to the mathematical extraction of the noise sources versus biasing and under different thermal stress conditions to find the origin of G-R centers. A correlation between this study and SIMS measurements is presented. The last section of this work deals with large signal modelling and X-band oscillator: an original, accurate and fast modelling technique is proposed as an alternative to the usually time consuming traditional techniques. Thus the oscillator is designed, and its performances are discussed (POUT=20dBm, Lf(100kHz)=-105 dBc/Hz at 10 GHz).
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Submitted on : Monday, June 11, 2007 - 2:49:09 PM
Last modification on : Thursday, June 10, 2021 - 3:07:06 AM
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  • HAL Id : tel-00153628, version 1


Geoffroy Soubercaze-Pun. De l'étude en bruit basse fréquence à la conception d'un oscillateur en bande-X à partir de transistors AlGaN/GaN HEMT. Micro et nanotechnologies/Microélectronique. Université Paul Sabatier - Toulouse III, 2007. Français. ⟨tel-00153628⟩



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