Dresden 2011 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 42: Poster I: Progress in Micro- and Nanopatterning: Techniques and Applications (jointly with O); Spins in Organic Materials; Ion Interactions with Nano Scale Materials; Organic Electronics and Photovoltaics; Plasmonics and Nanophotonics (jointly with HL and O); High-k and Low-k Dielectrics (jointly with DF); Organic Thin Films; Nanoengineered Thin Films; Layer Deposition Processes; Layer Properties: Electrical, Optical, and Mechanical Properties; Thin Film Characterisation: Structure Analysis and Composition; Application of Thin Films
DS 42.122: Poster
Mittwoch, 16. März 2011, 15:00–17:30, P1
Dielectric function of ultra-thin high-k films grown by atomic layer deposition — •Li Ding1, Lin Chen2, Marion Friedrich1, Ovidiu Gordan1, Wei Zhang2, and Dietrich Zahn1 — 1Semiconductor Physics, Chemnitz University of Technology, D-09107, Germany — 2State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, Shanghai 200433, China
High-k dielectrics are intensively studied to replace the conventionally used SiO2 as gate dielectrics in various electronic devices [1]. Hafnium dioxide (HfO2) is one of the candidates due to a high k value, a wide band gap around 6.4 eV, and a good thermal stability [2]. HfO2 usually forms crystalline structures, but amorphous films are preferred to minimize leakage currents through dielectric layers. It is possible to obtain amorphous films by growing HfO2 together with another compound, such as Al2O3, which stays amorphous at much higher temperatures.
Two series of samples were prepared by atomic layer deposition (ALD). One series consists of alloy films with different component ratios between HfO2 and Al2O3, while the other consists of bilayer films with various layer thicknesses. In order to investigate the influence of the film thickness and layer structure on the band gap, a vacuum ultraviolet (VUV) ellipsometer (4.0-9.8 eV) is employed using synchrotron radiation as a light source. Moreover, a laboratory spectroscopic ellipsometer (0.7-5 eV) is used to determine the film thickness.
[1] J. Appl. Phys. 89, 5243 (2001). [2] Microelectron. Eng. 69, 145 (2003).