Electrical and Optical Characterization of Ni/Al0.3Ga0.7N/GaN Schottky Barrier Diodes

• Published in: Journal of electronic materials Vol. 41; no. 11; pp. 3017 - 3020
• Main Authors: Kordoš, P., Škriniarová, J., Chvála, A., Florovič, M., Kováč, J., Donoval, D.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.11.2012; Springer
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Interfaces; Materials; Materials Science; Optical and Electronic Materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solid State Physics; Surface double layers, schottky barriers, and work functions; transport mechanisms; dislocation density; AlGaN/GaN; Schottky barrier; Photoelectron spectra; Temperature dependence; Electronic properties; Electrical properties; Schottky barriers; Tunnel effect; Gallium nitride; III-V compound; Dislocation density; Electrical measurement; Thermionic emission; Temperature effects; Photoemission; Optical properties; Schottky barrier diodes; Nickel; Barrier height; IV characteristic; III-V semiconductors
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-012-2184-5

Ni/AlGaN/GaN Schottky barrier diodes were characterized by electrical and optical measurements. Analysis of temperature-dependent (80 K to 550 K) current–voltage characteristics considering various transport mechanisms shows that the tunneling current dominates in the samples investigated. Thermionic emission current, extracted from the total current by a fitting procedure, yielded an effective barrier height of 1.36 eV to 1.39 eV at 300 K, and its slight decrease with increased temperature. This result shows that significantly lower barrier heights reported before (0.73 eV to 0.96 eV) follow from an assumption that the measured and thermionic currents are equal. The barrier height of 1.66 eV extracted from photoemission measurements confirms that electrically evaluated barrier heights are underestimated. The tunneling current contribution is considered to be dislocation governed, and a dislocation density of about 2 × 10 8  cm −2 is calculated.