OFF-State Degradation of AlGaN/GaN Power HEMTs: Experimental Demonstration of Time-Dependent Drain-Source Breakdown

• Published in: IEEE transactions on electron devices Vol. 61; no. 6; pp. 1987 - 1992
• Main Authors: Meneghini, Matteo, Cibin, Giulia, Bertin, Marco, Hurkx, Godefridus Adrianus Maria, Ivo, Ponky, Sonsky, Jan, Croon, Jeroen A., Meneghesso, Gaudenzio, Zanoni, Enrico
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-06-2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum gallium nitride; Breakdown; Constants; Degradation; Electric potential; Gallium nitride; Gallium nitrides; GaN; HEMTs; high electron mobility transistor (HEMT); High electron mobility transistors; Logic gates; MODFETs; reliability; Semiconductor devices; Stress; Stresses; Breakdown; high electron mobility transistor (HEMT); GaN; reliability
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2014.2318671

This paper reports the experimental demonstration of a novel degradation mechanism of high-power AlGaN/GaN high electron mobility transistors (HEMTs), that is, time-dependent drain-source breakdown. With current-controlled breakdown measurements and constant voltage stress experiments we demonstrate that: 1) when submitted to constant voltage stress, in the OFF-state, the HEMTs can show a significant degradation; 2) the degradation process is time-dependent, and consists of a measurable increase in subthreshold drain-source leakage; this effect is ascribed to the accumulation of positive charge in proximity of the gate, consistently with previous theoretical calculations; and 3) a catastrophic (and permanent) failure is observed for long stress times, possibly due to thermal runaway or to the increase in the electric field in proximity of the localized drain-source leakage paths.