On the redox origin of surface trapping in AlGaN/GaN high electron mobility transistors

Journal Article · Fri Mar 28 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4869738· OSTI ID:22271143

Gao, Feng ^[1]; Chen, Di; Tuller, Harry L.; Thompson, Carl V. ^[2]; Palacios, Tomás ^[1]

---

1. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2. Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

Water-related redox couples in ambient air are identified as an important source of the surface trapping states, dynamic on-resistance, and drain current collapse in AlGaN/GaN high electron mobility transistors (HEMTs). Through in-situ X-ray photoelectron spectroscopy (XPS), direct signature of the water-related species—hydroxyl groups (OH) was found at the AlGaN surface at room temperature. It was also found that these species, as well as the current collapse, can be thermally removed above 200 °C in vacuum conditions. An electron trapping mechanism based on the H{sub 2}O/H{sub 2} and H{sub 2}O/O{sub 2} redox couples is proposed to explain the 0.5 eV energy level commonly attributed to the surface trapping states. Finally, the role of silicon nitride passivation in successfully removing current collapse in these devices is explained by blocking the water molecules away from the AlGaN surface.

• OSTI ID: 22271143
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM COMPOUNDS
CHANNELING
ELECTRIC CONDUCTIVITY
ELECTRON MOBILITY
ELECTRONS
ENERGY LEVELS
GALLIUM NITRIDES
HETEROJUNCTIONS
INTERFACES
SILICON NITRIDES
SURFACES
TEMPERATURE RANGE 0273-0400 K
TRANSISTORS
TRAPPING
WATER
X-RAY PHOTOELECTRON SPECTROSCOPY