Temperature measurement by micro-Raman scattering spectroscopy in the active zone of AlGaN/GaN high-electron-mobility transistors

¹ Thales Research and Technology, Domaine de Corbeville, 91404 Orsay Cedex, France
² CRHEA-CNRS, rue Bernard Gregory, 06560 Valbonne, France

Corresponding author: raphael.aubry@thalesgroup.com

Received: 9 July 2003
Accepted: 18 December 2003
Published online: 15 July 2004

Abstract

The high power RF device performance decreases as the operation temperature increases (e.g. fall of electron mobility impacting the cut-off frequencies and degradation of device reliability). Therefore the determination of device temperature is a key issue for device topology optimisation. In this work the temperature variation of AlGaN/GaN high-electron-mobility transistors grown either on silicon or sapphire substrates under bias operation was measured by micro Raman scattering spectroscopy. The differences in thermal resistance for similar devices grown on the two different substrates were assessed. The thermal resistances of different device topologies were compared in order to optimise the component design. The temperature measurement across the gate and along the component fingers were made to quantify the thermal gradient of the device. Temperature measurement up to a power dissipation of 16 W for a 4 mm development device was carried out and the peak temperature of 650 K was determined.