Solution based synthesis and electronic characterisation of interface controlled amorphous oxidic multilayer films

• Applicant: Professor Dr. Jörg J. Schneider
• Subject Area: Synthesis and Properties of Functional Materials ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 358048032

Multilayer systems of indium zinc oxide (IZO, semiconductor) and zirconium dioxide (ZrO2, dielectric) will be accessed by solution processing routes with the aim to study their properties as metal oxide/semiconductor capacity as well as field effect transistors. Synthetically, molecular single source precursor molecules will be employed. These compounds are applicable for thin film deposition by spincoating directly in solutions or by the intermediate conversion to stable dispersion of nanoparticles therefrom. In both cases a subsequent thermal processing is required in order to obtain the functional oxide layers. Appropriate device designs and processing conditions must be found for the fabrication of the MOS capacities and FETs, under which performance parameters as high as possible can be obtained. The successive deposition of the layers should therefore avoid material degradation within the layer sequence and change initial material properties as little as possible. Inherently to the fabrication procedure subsequent processing steps influence the electrical properties of already present layers. Thus, surface adsorbates, defect chemistry and interface effects play a much higher role in film deposition from solution. The electrical measurements enable an assessment of the different fabrication conditions (temperature, heating rate, reaction atmosphere) and device arrangements (film thickness and spatial dimensions). Finally carrier density in the oxidic dielectric, interface charge density as well the difference in the work function between dielectric and semiconductor can be determined. Further propositions should be possible with respect to the conduction mechanism in the dielectric and device break-down. These measurements will be complemented by microscopic and spectroscopic investigations in order to gain a comprehensive picture of the structural and electronic properties. This course of action will allow a target-oriented development of the device architecture and the determination of the process conditions. The entirety of this work will allow conclusions with respect to the functionality of the solution processed multilayer oxide material IZO/ZrO2 as well as to the specific challenges of a more general fabrication and operation of complex devices.

• DFG Programme: Research Grants