Electrical and structural characterizations of crystallized Al{sub 2}O{sub 3}/GaN interfaces formed by in situ metalorganic chemical vapor deposition

Journal Article · Thu Jan 07 00:00:00 EST 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4939157· OSTI ID:22494870

Yeluri, R.; Kim, J.; Keller, S.; Mishra, U. K. ^[1]; Jackson, C. M.; Arehart, A. R.; Ringel, S. A. ^[2]; Wu, F.; Mazumder, B.; Speck, J. S. ^[3]

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1. Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)
2. Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)
3. Materials Department, University of California, Santa Barbara, California 93106 (United States)

Al{sub 2}O{sub 3} films were grown in situ by metalorganic chemical vapor deposition at 900 °C on GaN of both Ga- and N-face polarities. High-resolution transmission electron microscopy revealed that the Al{sub 2}O{sub 3} films were crystalline and primarily γ-phase. The Al{sub 2}O{sub 3}/Ga-GaN and Al{sub 2}O{sub 3}/N-GaN interfaces were both atomically sharp, and the latter further exhibited a biatomic step feature. The corresponding current-voltage (J-V) characteristics were measured on a metal-Al{sub 2}O{sub 3}-semiconductor capacitor (MOSCAP) structure. The leakage current was very high when the Al{sub 2}O{sub 3} thickness was comparable with the size of the crystalline defects, but was suppressed to the order of 1 × 10{sup −8} A/cm{sup 2} with larger Al{sub 2}O{sub 3} thicknesses. The interface states densities (D{sub it}) were measured on the same MOSCAPs by using combined ultraviolet (UV)-assisted capacitance-voltage (C-V), constant capacitance deep level transient spectroscopy (CC-DLTS), and constant capacitance deep level optical spectroscopy (CC-DLOS) techniques. The average D{sub it} measured by CC-DLTS and CC-DLOS were 6.6 × 10{sup 12} and 8.8 × 10{sup 12} cm{sup −2} eV{sup −1} for Al{sub 2}O{sub 3}/Ga-GaN and 8.6 × 10{sup 12} and 8.6 × 10{sup 12 }cm{sup −2} eV{sup −1} for Al{sub 2}O{sub 3}/N-GaN, respectively. The possible origins of the positive (negative) polarization compensation charges in Al{sub 2}O{sub 3}/Ga-GaN (Al{sub 2}O{sub 3}/N-GaN), including the filling of interface states and the existence of structure defects and impurities in the Al{sub 2}O{sub 3} layer, were discussed in accordance with the experimental results and relevant studies in the literature.

• OSTI ID: 22494870
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 1; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALUMINIUM OXIDES
CAPACITANCE
CAPACITORS
CHEMICAL VAPOR DEPOSITION
CRYSTAL DEFECTS
DEEP LEVEL TRANSIENT SPECTROSCOPY
DENSITY OF STATES
ELECTRIC POTENTIAL
FILMS
GALLIUM NITRIDES
INTERFACES
LEAKAGE CURRENT
SEMICONDUCTOR MATERIALS
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY
ULTRAVIOLET RADIATION