High-efficiency GaN HEMTs on 3-inch semi-insulating SiC substrates

✍ Scribed by Waltereit, P. ;Bronner, W. ;Quay, R. ;Dammann, M. ;Müller, S. ;Kiefer, R. ;Raynor, B. ;Mikulla, M. ;Weimann, G.

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 358 KB
• Volume: 205
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200778442

✦ Synopsis

Abstract

We report on device performance and reliability of our 3″ GaN high electron mobility transistor (HEMT) technology. AlGaN/GaN HEMT structures are grown on semi‐insulating SiC substrates by metal‐organic chemical vapor deposition (MOCVD) with sheet resistance uniformities better than 2%. Device fabrication is performed using standard processing techniques involving both e‐beam and stepper lithography. AlGaN/GaN HEMTs demonstrate excellent high‐voltage stability and large efficiencies. Devices with 0.5 µm gate length exhibit two‐terminal gate‐drain breakdown voltages in excess of 160 V and drain currents well below 1 mA/mm when biased at 80 V drain bias under pinch‐off conditions. Load‐pull measurements at 2 GHz return both a linear relationship between drain bias voltage and output power as well as power added efficiencies beyond 55% up to 72 V drain bias for which an output power density of 9 W/mm with 25 dB linear gain is obtained. Reliability tests indicate a promising device stability under both radio frequency (RF) and direct current (DC) stress conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)