We show the results of stressing GaN HEMTs at extremely high gate current densities but for longer times and with more positive results. VGon, showed that there was little degradation in drain and source resistances and maximum drain current. The authors concluded that the large forward gate current and high temperature degraded the Schottky contact. By stepping VG from +0.5 V to +6V in 0.5 V steps for 30 minutes per step, a reduction in VGon (VG at a normalized gate current of 1 mA/mm) after 360 minutes was observed, accompanied by about a 104 increase in gate leakage current and strong Ohmic gate behavior. Reference specifically considered the effects of high positive gate bias (up to +6V) on GaN HEMTs with gate-integrated field plates, Lg = 0.25^m, and Wg = 2 X 25^m. The semi-insulating Fe-doped GaN of was grown by MOCVD on sapphire substrates. GaN HEMTs (Lg = 0.7pm, Wg = 2 X 100^m) in reached about 400mA/mm forward gate current before burning out. Other reports state that forward gate current limits the survival times of GaN HEMTs, especially during RF operation. The signature of this degradation mechanism is an increase in gate leakage current. There are recent reports stating that high negative gate bias causes the gates of GaN HEMTs to degrade. We report an extremely robust GaN HEMT technology that survived-contrary to conventional wisdom-high forward gate bias (+6V) and current (>1.8 A/mm) for >17.5 hours exhibiting only a slight change in gate diode characteristic, little decrease in maximum drain current, with only a 0.1 V positive threshold voltage shift, and, remarkably, a persisting breakdown voltage exceeding 200 V. Reports to date of GaN HEMTs subjected to forward gate bias stress include varied extents of degradation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Christiansen, Received 21 March 2012 Revised 10 July 2012 Accepted 28 July 2012 Academic Editor: Jung-Hui TsaiĬopyright © 2012 Bradley D.
Sheal圓ġĝepartment of Electrical and Computer Engineering, Air Force Institute of Technology, Wright-Patterson Air Force Base, OH 45433, USAĢ Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433, USAģĝefense and Power Business Unit, RF Micro Devices, Inc., Charlotte, NC 28269, USAĬorrespondence should be addressed to Bradley D. Coutu Jr.,1 Ramakrishna Vetury,3 and Jeffrey B. Hindawi Publishing Corporation Active and Passive Electronic Components Volume 2012, Article ID 493239, 4 pages doi:10.1155/2012/493239Ī Very Robust AlGaN/GaN HEMT Technology to High Forward Gate Bias and Currentīradley D.
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