Strong effect of scandium source purity on chemical and electronic properties of epitaxial ScxAl1−xN/GaN heterostructures
Abstract
Epitaxial multilayer heterostructures of ScxAl1−xN/GaN with Sc contents x = 0.11–0.45 are found to exhibit significant differences in structural quality, chemical impurity levels, and electronic properties depending on the starting Sc source impurity levels. A higher purity source leads to a 2–3 orders of magnitude reduction in the carbon, oxygen, and fluorine unintentional doping densities in MBE-grown ScxAl1−xN/GaN multilayers. Electrical measurements of ScxAl1−xN/n+GaN single heterostructure barriers show a 5–7 orders of magnitude reduction in the electrical leakage for films grown with a higher purity Sc source at most Sc contents. The measured chemical and electrical properties of epitaxial ScxAl1−xN highlight the importance of the starting Sc source material purity for epitaxial device applications that need these highly piezoelectric and/or ferroelectric transition-metal nitride alloys.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 01, 2021
- Source ID
- 10.1063/5.0054522
Entities
People
- Celesta S. Chang
- David A. Muller
- Debdeep Jena
- Huili Grace Xing
- Hyunjea Lee
- Joseph Casamento
- M.F. Besser
- Takuya Maeda
Organizations
- Air Force Office of Scientific Research
- Ames National Laboratory
- Cornell University
- Defense Advanced Research Projects Agency
- National Science Foundation