Analysis of leakage current mechanisms in Schottky contacts to GaN and Al{sub 0.25}Ga{sub 0.75}N/GaN grown by molecular-beam epitaxy
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093-0407 (United States)
Temperature-dependent current-voltage measurements combined with conductive atomic force microscopy and analytical modeling have been used to assess possible mechanisms of reverse-bias leakage current flow in Schottky diodes fabricated from GaN and Al{sub 0.25}Ga{sub 0.75}N/GaN structures grown by molecular-beam epitaxy. Below 150 K, leakage current is nearly independent of temperature, indicating that conduction is dominated by tunneling transport. At higher temperatures, leakage current in both GaN and Al{sub 0.25}Ga{sub 0.75}N/GaN diode structures is well described by a Frenkel-Poole emission model. Based on the inferred emission barrier heights and the observation that room-temperature leakage current is dominated by the presence of highly conductive dislocations, it is suggested that the key carrier transport process is emission of electrons from a trap state near the metal-semiconductor interface into a continuum of states associated with each conductive dislocation. In this model for leakage current flow, the emission barrier heights measured for the GaN and Al{sub 0.25}Ga{sub 0.75}N/GaN diode structures indicate that the conductive dislocation states are aligned in energy between GaN and Al{sub 0.25}Ga{sub 0.75}N.
- OSTI ID:
- 20787798
- Journal Information:
- Journal of Applied Physics, Vol. 99, Issue 2; Other Information: DOI: 10.1063/1.2159547; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM COMPOUNDS
ATOMIC FORCE MICROSCOPY
CHARGE CARRIERS
CHARGED-PARTICLE TRANSPORT
CRYSTAL GROWTH
DISLOCATIONS
ELECTRIC POTENTIAL
ELECTRONS
EMISSION
GALLIUM NITRIDES
INTERFACES
LEAKAGE CURRENT
MOLECULAR BEAM EPITAXY
SCHOTTKY BARRIER DIODES
SEMICONDUCTOR MATERIALS
SIMULATION
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TUNNEL EFFECT