Conductivity and distribution of charge on electroluminescent Si/SiO2 structures investigated by electrostatic force microscopy

• Published in: Applied surface science 2004-01, Vol.222 (1-4), p.131-137
• Main Authors: Suominen, T, Paturi, P, Huhtinen, H, Heikkilä, L, Hedman, H.-P, Punkkinen, R, Laiho, R
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity processes; Electrical properties of specific thin films; Electrical properties of specific thin films and layer structures (multilayers, superlattices, quantum wells, wires, and dots); Electroluminescence; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electrostatic force microscopy; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other luminescence and radiative recombination; Physics; Silicon/silicon dioxide; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2003.08.004

Electroluminescent Si/SiO2/Au layer structures on a p-Si wafer are investigated with electrostatic force microscopy and atomic force microscopy. The samples comprise either four Si/SiO2 layer pairs prepared by chemical vapor deposition or a SiO2 thermal oxide layer grown at 950°C on the wafer. A 9–13nm thick Au-film electrode is sputtered on top of the samples. A correlation between the density of electroluminescent dots and distribution of charge on the surface of these structures is found. Measurements of the excitation current through the samples show that the four-layer Si/SiO2/Au structure has Poole–Frenkel type conductivity and the thermal oxide sample is excited through Fowler–Nordheim tunneling.