| AVS 65th International Symposium & Exhibition | |
| Electronic Materials and Photonics Division | Wednesday Sessions |
| Session EM+2D+SS-WeA |
| Session: | Wide and Ultra-Wide Bandgap Materials for Electronic Devices: Growth, Modeling and Properties |
| Presenter: | Erica Douglas, Sandia National Laboratories |
| Authors: | E.A. Douglas, Sandia National Laboratories B. Klein, Sandia National Laboratories S. Reza, Sandia National Laboratories A.A. Allerman, Sandia National Laboratories R.J. Kaplar, Sandia National Laboratories A.M. Armstrong, Sandia National Laboratories A.G. Baca, Sandia National Laboratories |
| Correspondent: | Click to Email |
Recently, ultra-wide bandgap (UWBG) materials, such as Al-rich AlGaN with bandgaps approaching 6 eV, are being investigated to drive high-power electronic applications to even higher voltages, due to increased critical electric field compared to wide bandgap materials, such as GaN.1 However, challenges have been encountered with Al-rich AlGaN, and in particular an increase in contact resistance as the bandgap for heterostructures increases.2 High contact resistance ultimately limits the performance that can be achieved for these novel heterostructure-based devices, as source and drain resistances can be dominated by Ohmic contacts. While planar metal stacks with a rapid thermal anneal have shown some level of success, a complimentary approach using doped regrowth for the Ohmic contact regions with materials of lower bandgap has also shown a potential path for lowering contact resistance.2 Our work explores regrown Ohmic contacts composed of lower bandgap Si-doped GaN to Al0.85Ga0.15N/Al0.7Ga0.3N heterostructures , achieving a maximum saturated drain current of ~ 45mA/mm. Additionally, we demonstrate the ability to increase the saturated drain current almost 3X (from ~45 mA/mm to ~130 mA/mm) for UWBG HEMTs through a circular perforation design as well as a comb-type structure by means of regrowth contact design engineering.
1 R. J. Kaplar, et. al, “Review—Ultra-Wide-Bandgap AlGaN Power Electronic Devices,” ECS J. Solid State Sci. Technol., vol. 6, no. 2, pp. Q3061-Q3066, Jan. 2017.
2 B. A. Klein, et. al, “Planar Ohmic Contacts to Al0.45Ga0.55N/Al0.3Ga0.7N High Electron Mobility Transistors,” ECS J. Solid State Sci. Technol., vol. 6, no. 11, pp. S3067-S3071, Aug. 2017.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA-0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government.