Comparison of the physical, chemical and electrical properties of ALD Al 2 O 3 on c- and m- plane GaN: Comparison of the physical, chemical and electrical properties of ALD Al 2 O 3 on c- and m- plane GaN
- Kansas State Univ., Manhattan, KS (United States)
- Naval Research Lab. (NRL), Washington, DC (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Our study compares the physical, chemical and electrical properties of Al2O3 thin films deposited on gallium polar c- and nonpolar m -plane GaN substrates by atomic layer deposition (ALD). Correlations were sought between the film's structure, composition, and electrical properties. The thickness of the Al2O3 films was 19.2 nm as determined from a Si witness sample by spectroscopic ellipsometry. We measured the gate dielectric was slightly aluminum-rich (Al:O=1:1.3) from X-ray photoelectron spectroscopy (XPS) depth profile, and the oxide-semiconductor interface carbon concentration was lower on c -plane GaN. The oxide's surface morphology was similar on both substrates, but was smoothest on c -plane GaN as determined by atomic force microscopy (AFM). Circular capacitors (50-300 μm diameter) with Ni/Au (20/100 nm) metal contacts on top of the oxide were created by standard photolithography and e-beam evaporation methods to form metal-oxide-semiconductor capacitors (MOSCAPs). Moreover, the alumina deposited on c -plane GaN showed less hysteresis (0.15 V) than on m -plane GaN (0.24 V) in capacitance-voltage (CV) characteristics, consistent with its better quality of this dielectric as evidenced by negligible carbon contamination and smooth oxide surface. These results demonstrate the promising potential of ALD Al2O3 on c -plane GaN, but further optimization of ALD is required to realize the best properties of Al2O3 on m -plane GaN.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Temperature Materials Lab. (HTML)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
- DOE Contract Number:
- AC05-00OR22725; N0014-09-1-1160
- OSTI ID:
- 1265776
- Journal Information:
- Physica Status Solidi C, Vol. 11, Issue 3-4; ISSN 1862-6351
- Publisher:
- Wiley
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electrical and structural characterizations of crystallized Al{sub 2}O{sub 3}/GaN interfaces formed by in situ metalorganic chemical vapor deposition
Atomic layer deposition TiO2-Al2O3 stack: An improved gate dielectric on Ga-polar GaN metal oxide semiconductor capacitors