Enhancement-Mode AlGaN/GaN MIS-HEMTs With High VTH and High IDmax Using Recessed-Structure With Regrown AlGaN Barrier

We report on an Al
₂
O
₃
/AlGaN/GaN metalinsulator-semiconductor high-electron-mobility transistor (MIS-HEMT) with recessed-gate structure and regrown AlGaN barrier. After analyzing the possibility of obtaining high threshold voltage (V
_th
) within the framework of Tapajna and Kuzmik model from preliminary experiments using MIS-diode structures, we fabricated a MIS-HEMT with the same materials and structures. The transistor exhibited a highVth value of +2.3 V determined at the drain current criterion of 10
_μ
A/mm together with a maximum drain current density (I
_Dmax
) of 425 mA/mm. We believe that the adoption of a technology, i. e., AlGaN regrowth on dryetched GaN surface, previously demonstrated by our group in planar device, is the main key for achieving such desirable performance.