Environmental stability of candidate dielectrics for GaN-based device applications

Journal Article · Thu Oct 01 04:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3236568· OSTI ID:21361871

Herrero, A M; Gila, B P; Gerger, A; Scheuermann, A; Davies, R; Abernathy, C R; Pearton, S J; Ren, F ^[1]

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1. Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States)

The thermal and chemical stability of potential dielectrics for GaN-based devices in a GaN metal organic chemical vapor deposition (MOCVD) environment is investigated, and their suitability for use as a gate dielectric and as a regrowth mask for the selective area growth of GaN is discussed. Thin films of MgO, Sc{sub 2}O{sub 3}, and Sc{sub 2}O{sub 3}/MgO were grown by molecular beam epitaxy on GaN/sapphire substrates and then annealed in a MOCVD reactor under GaN growth conditions except for the lack of trimethylgallium. All films were processed into metal-oxide-semiconductor diodes and were characterized before and after being annealed using atomic force microscopy, x-ray reflectivity, x-ray photoelectron spectroscopy, current-voltage (I-V), and capacitance-voltage (C-V) measurements. The Gibbs free energy of all possible reactions was calculated, and their probability and possible influence on the characterization results is examined. After being annealed, the atomic force microscopy of the oxide films showed some degree of roughening for all of them. Despite the surface roughening, all the oxide films examined showed potential for use as a regrowth mask. The MOCVD anneal caused the electrical properties of the MgO film to degrade considerably, and the Sc{sub 2}O{sub 3} films were unable to be electrically characterized after annealing due to shorting, which is believed to be caused by the formation of a ScN layer on the surface. The effect of the thickness of the Sc{sub 2}O{sub 3} cap for MgO films was investigated. The characterization results indicate that the Sc{sub 2}O{sub 3} film dissolved into MgO during annealing and that a ScN film did not form on the surface. Of all the oxide films examined in this study, the Sc{sub 2}O{sub 3}/MgO stack with the thinner Sc{sub 2}O{sub 3} cap exhibited the greatest stability with respect to its electrical properties.

• OSTI ID: 21361871
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 106; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
ATOMIC FORCE MICROSCOPY
CAPACITANCE
CHALCOGENIDES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
CORUNDUM
CRYSTAL GROWTH
CRYSTAL GROWTH METHODS
DEPOSITION
DIELECTRIC MATERIALS
ELECTRIC POTENTIAL
ELECTRICAL PROPERTIES
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
EPITAXY
FILMS
FREE ENERGY
FREE ENTHALPY
GALLIUM COMPOUNDS
GALLIUM NITRIDES
HEAT TREATMENTS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MATERIALS
METALS
MICROSCOPY
MINERALS
MOLECULAR BEAM EPITAXY
NITRIDES
NITROGEN COMPOUNDS
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PHYSICAL PROPERTIES
PNICTIDES
PROBABILITY
REFLECTION
REFLECTIVITY
ROUGHNESS
SAPPHIRE
SCANDIUM COMPOUNDS
SCANDIUM NITRIDES
SCANDIUM OXIDES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SEMICONDUCTOR MATERIALS
SPECTROSCOPY
SUBSTRATES
SURFACE COATING
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
X-RAY PHOTOELECTRON SPECTROSCOPY