1. AlGaN channel field effect transistors with graded heterostructure ohmic contacts.
- Author
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Bajaj, Sanyam, Akyol, Fatih, Krishnamoorthy, Sriram, Zhang, Yuewei, and Rajan, Siddharth
- Subjects
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GALLIUM nitride , *FIELD-effect transistors , *BAND gaps , *METAL-insulator-semiconductor devices , *OHMIC resistance , *SCHOTTKY barrier - Abstract
We report on ultra-wide bandgap (UWBG) Al0.75Ga0.25N channel metal-insulator-semiconductor field-effect transistors (MISFETs) with heterostructure engineered low-resistance ohmic contacts. The low intrinsic electron affinity of AlN (0.6 eV) leads to large Schottky barriers at the metal-AlGaN interface, resulting in highly resistive ohmic contacts. In this work, we use a reverse compositional graded n++ AlGaN contact layer to achieve upward electron affinity grading, leading to a low specific contact resistance (ρsp) of 1.9×10-6 Ω cm² to n-Al0.75Ga0.25N channels (bandgap ∼5.3 eV) with non-alloyed contacts. We also demonstrate UWBG Al0.75Ga0.25N channel MISFET device operation employing the compositional graded n++ ohmic contact layer and 20 nm atomic layer deposited Al2O3 as the gate-dielectric. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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