AlGaN channel field effect transistors with graded heterostructure ohmic contacts
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 26, 2016
- Source ID
- 10.1063/1.4963860
Entities
People
- Fatih Akyol
- Sanyam Bajaj
- Siddharth Rajan
- Sriram Krishnamoorthy
- Yuewei Zhang
Organizations
- National Science Foundation
- Office of Naval Research
- Ohio State University