Effect of OFF-state stress induced electric field on trapping in AlGaN/GaN high electron mobility transistors on Si (111)
Anand, M. J.
Ng, G. I.
Manoj Kumar, C. M.
Foo, S. C.
Date of Issue2015
School of Electrical and Electronic Engineering
Research Techno Plaza
The influence of electric field (EF) on the dynamic ON-resistance (dyn-R DS[ON]) and threshold-voltage shift (ΔVth) of AlGaN/GaN high electron mobility transistors on Si has been investigated using pulsed current-voltage (IDS-VDS) and drain current (ID) transients. Different EF was realized with devices of different gate-drain spacing (Lgd) under the same OFF-state stress. Under high-EF (Lgd = 2 μm), the devices exhibited higher dyn-R DS[ON] degradation but a small ΔVth (∼120 mV). However, at low-EF (Lgd = 5 μm), smaller dyn-R DS[ON] degradation but a larger ΔVth (∼380 mV) was observed. Our analysis shows that under OFF-state stress, the gate electrons are injected and trapped in the AlGaN barrier by tunnelling-assisted Poole-Frenkel conduction mechanism. Under high-EF, trapping spreads towards the gate-drain access region of the AlGaN barrier causing dyn-R DS[ON] degradation, whereas under low-EF, trapping is mostly confined under the gate causing ΔVth. A trap with activation energy 0.33 eV was identified in the AlGaN barrier by ID-transient measurements. The influence of EF on trapping was also verified by Silvaco TCAD simulations.
DRNTU::Engineering::Electrical and electronic engineering::Electronic systems
Applied physics letters
© 2015 AIP Publishing LLC. This paper was published in Applied Physics Letters and is made available as an electronic reprint (preprint) with permission of AIP Publishing LLC. The paper can be found at the following official DOI: [http://dx.doi.org/10.1063/1.4913841]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.