David I. Shahin1, Travis J. Anderson2, Virginia D. Wheeler2, Marko J. Tadjer2, Andrew D. Koehler2, Karl D. Hobart2, Charles R. Eddy Jr.2, Francis J. Kub2, and Aris Christou1
1 Department of Materials Science and Engineering, University of Maryland, College Park, MD, USA
2 Naval Research Laboratory, Washington, DC 20375, USA
Abstract:
TiN, a transition metal nitride, has been evaluated as an electrically and thermally stable Schottky gate material for AlGaN/GaN high
electron mobility transistors. HEMTs with 75 nm TiN gates deposited via atomic layer deposition at 350◦C exhibited improved static
and dynamic on-state characteristics compared to Ni/Au-gated HEMTs. Reverse bias gate stressing indicated a higher critical voltage
and higher breakdown voltage for the TiN-gated HEMTs. The TiN gated devices exhibited stable DC operation after annealing
at temperatures as high as 800◦C, while the Ni/Au gates exhibited significant degradation after annealing above 500◦C and failed
catastrophically at 800◦C.
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