We investigate the polarization modulation effect of a single-crystalline BeO layer on AlGaN/GaN high-electron-mobility transistors (HEMTs). The BeO layer with macroscopic polarization on top of the AlGaN barrier layer increases the 2-dimensional electron gas density in the triangular quantum well (QW) at the interface of the AlGaN/GaN heterostructure. Electronic band bending of BeO and a deeper triangular QW observed from the simulated conduction band profile indicate that the BeO layer can modify the polarization field at the AlGaN/GaN interface. A ∼20-nm-thick single-crystalline BeO thin film is grown on AlGaN/GaN HEMTs by atomic-layer deposition. Room-temperature and variable-temperature Hall-effect measurements confirm that the HEMT with BeO forms a channel with a 14% increase of the sheet carrier concentration as compared with a conventional HEMT. An improved output performance is also observed in the I-V characteristics which confirms the polarization modulation effect of the BeO layer.
Bibliographical noteFunding Information:
This material is based upon work at the University of Houston supported by the National Science Foundation under Grant No. 1842299 [Electrical, Communications and Cyber Systems (ECCS)]. J.-H.R. also acknowledges partial support from the Texas Center for Superconductivity at the University of Houston (TcSUH) and the Advanced Manufacturing Institute (AMI). The study at Yonsei University was supported by the MIST (Ministry of Science and ICT), Korea, under the “ICT Consilience Creative Program” (IITP-2019-2017-0-01015) supervised by the IITP (Institute for Information & Communications Technology Promotion) and by the Korea Electric Power Corporation (under Grant No. R18XA06-03). Funding for efforts by the Pennsylvania State University was provided by the AFOSR Young Investigator Program (Grant No. FA9550-17-1-0141, Program Officers: Dr. Brett Pokines and Dr. Michael Kendra. This work was also monitored by Dr. Kenneth Goretta).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)