Details

Autor(en) / Beteiligte

• Bajaj, Sanyam
• Akyol, Fatih
• Krishnamoorthy, Sriram
• Zhang, Yuewei
• Rajan, Siddharth

Titel

AlGaN channel field effect transistors with graded heterostructure ohmic contacts

Ist Teil von

• Applied physics letters, 2016-09, Vol.109 (13)

Ort / Verlag

Melville: American Institute of Physics

Erscheinungsjahr

2016

Quelle

AIP Journals (American Institute of Physics)

Beschreibungen/Notizen

• 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.