Growth and Characterization of Nitrogen-Polar AlGaN/AlN Heterostructure for High-Electron-Mobility Transistor
Abstract
A nitrogen-polar (N-polar) AlGaN/AlN high-electron-mobility transistor (HEMT) is proposed, and the generation of a 2D electron gas (2DEG) is simulated. The band diagram of N-polar (Al)GaN/AlN shows the generation of the 2DEG, whereas that of the conventional metal-polar (Al)GaN/AlN structure shows the generation of a 2D hole gas. Furthermore, the concentration of the 2DEG is considerably high even when the (Al)GaN layer is as thin as a few nanometers. N-polar AlGaN/AlN is grown on sapphire substrates with a misorientation angle of 2°; furthermore, atomic force microscope measurements in a range of 5 × 5 μm2 demonstrate that the root-mean-square value obtained from atomic force microscopy of N-polar AlGaN is approximately 0.7 nm. N-polar AlGaN layers with a thickness of approximately 40-60 nm with more than 50% Al content are almost coherently grown on the N-polar AlN layer with a thickness of approximately 400 nm.
- Publication:
-
Physica Status Solidi B Basic Research
- Pub Date:
- April 2020
- DOI:
- 10.1002/pssb.201900589
- Bibcode:
- 2020PSSBR.25700589I