ABSTRACT We report on studies about novel 3-aminopropyltrimethoxysilane (APTMS) based hybrid comp... more ABSTRACT We report on studies about novel 3-aminopropyltrimethoxysilane (APTMS) based hybrid composites doped by copper phthalocyanine (CuPc), [6,6]-phenyl-C61-butyric acid methyl ester and tris(dimethylvinylsilyloxy)–POSS (POSS). APTMS was used as siloxane matrix in order to produce thin layers of composite materials spin-coated onto silicon. The surface chemistry and the dielectric properties were investigated by the combination of X-ray photoelectron spectroscopy and capacitance voltage technique. We observed strong correlations between the dopant concentration and the chemical composition, homogeneity and electrical properties (permittivity, hysteresis) of the produced layers. Hence, an increase of the surfaces chemical resistance against the ambient conditions due to the POSS incorporation into the siloxane matrix was found. Furthermore, this work demonstrates that a properly chosen concentration of CuPc and POSS dopants within the siloxane matrix leads to homogenous films with an extremely low dielectric constant in the range of 1.8.
We report on the structural and electrical properties of Pr-based high-k dielectric films fabrica... more We report on the structural and electrical properties of Pr-based high-k dielectric films fabricated by solid-state reaction between metallic Pr and SiO 2 underlayers. A non-destructive depth profiling using synchrotron radiation excited photoelectron spectroscopy (SR-PES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were employed to examine the chemical composition and microstructure. Ab initio calculations were done to gain insight into the physical processes involved. SR-PES results indicate that Pr deposition at room temperature (RT) leads to the formation of a Pr silicide and a Pr oxide, what is in good agreement with the scenario expected from ab initio calculations. As revealed by TEM and electrical measurements, oxidation of the reacted structures, followed by annealing, results in a stacked dielectric composed of a SiO 2 -based buffer with an enhanced permittivity and a Pr silicate film with a high dielectric constant. The leakage current density of 10 À4 A/cm 2 was measured for stacks with capacitance equivalent thickness (CET) of 1.5 nm prepared by evaporation of the Pr layer on a 1.8 nm SiO 2 film, followed by oxidation in air ambient and annealing in N 2 atmosphere. The capacitance-voltage (C-V) curves exhibit a large flatband voltage (V FB ) shift indicating the presence of a positive charge in the stack. Switching away from the Al contacts to Au gate electrodes introduces a significant reduction of the V FB by 1.3 eV, what is much more than the change expected from the work function difference between Al and Au ($0.9 eV). This in turn implies that V FB is strongly affected by the gate interface electrode. r
ABSTRACT We report on studies about novel 3-aminopropyltrimethoxysilane (APTMS) based hybrid comp... more ABSTRACT We report on studies about novel 3-aminopropyltrimethoxysilane (APTMS) based hybrid composites doped by copper phthalocyanine (CuPc), [6,6]-phenyl-C61-butyric acid methyl ester and tris(dimethylvinylsilyloxy)–POSS (POSS). APTMS was used as siloxane matrix in order to produce thin layers of composite materials spin-coated onto silicon. The surface chemistry and the dielectric properties were investigated by the combination of X-ray photoelectron spectroscopy and capacitance voltage technique. We observed strong correlations between the dopant concentration and the chemical composition, homogeneity and electrical properties (permittivity, hysteresis) of the produced layers. Hence, an increase of the surfaces chemical resistance against the ambient conditions due to the POSS incorporation into the siloxane matrix was found. Furthermore, this work demonstrates that a properly chosen concentration of CuPc and POSS dopants within the siloxane matrix leads to homogenous films with an extremely low dielectric constant in the range of 1.8.
We report on the structural and electrical properties of Pr-based high-k dielectric films fabrica... more We report on the structural and electrical properties of Pr-based high-k dielectric films fabricated by solid-state reaction between metallic Pr and SiO 2 underlayers. A non-destructive depth profiling using synchrotron radiation excited photoelectron spectroscopy (SR-PES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were employed to examine the chemical composition and microstructure. Ab initio calculations were done to gain insight into the physical processes involved. SR-PES results indicate that Pr deposition at room temperature (RT) leads to the formation of a Pr silicide and a Pr oxide, what is in good agreement with the scenario expected from ab initio calculations. As revealed by TEM and electrical measurements, oxidation of the reacted structures, followed by annealing, results in a stacked dielectric composed of a SiO 2 -based buffer with an enhanced permittivity and a Pr silicate film with a high dielectric constant. The leakage current density of 10 À4 A/cm 2 was measured for stacks with capacitance equivalent thickness (CET) of 1.5 nm prepared by evaporation of the Pr layer on a 1.8 nm SiO 2 film, followed by oxidation in air ambient and annealing in N 2 atmosphere. The capacitance-voltage (C-V) curves exhibit a large flatband voltage (V FB ) shift indicating the presence of a positive charge in the stack. Switching away from the Al contacts to Au gate electrodes introduces a significant reduction of the V FB by 1.3 eV, what is much more than the change expected from the work function difference between Al and Au ($0.9 eV). This in turn implies that V FB is strongly affected by the gate interface electrode. r
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Papers by D. Schmitz