Thermal Decomposition of Hafnium Ethoxide-Mollecular Precursor for Hafnia Dielectric Thin Films

The HfO2 thin-film is a very promising gate dielectric material for last generation transistors. The paper presents the thermal decomposition of hafnium ethoxide used as molecular precursor for obtaining hafnia thin films. The investigated molecular precursor is a mixture of Hf3O(OC2H5)10 and Hf4O(OC2H5)14 moisture sensitive amorphous powder. The thermal decomposition of hafnium ethoxide precursor was investigated by TG-DTG-DSC analysis from room temperature to 600 oC in nitrogen atmosphere at 5 K/min. The composition of gas products resulted during pyrolytic decomposition has been studied by Fourier Transformation Infrared Spectroscopy (FTIR) and Mass Spectroscopy (MS). In the gas products, hydrogen, methyl, ethyl, vinyl, hydroxyl groups, acetic aldehyde and acetylene were identified. From mass spectroscopy and FTIR data results that the loss of ethoxy groups from the molecular precursor occurs in the decomposition steps between 200 and 375 oC. That suggests that in different steps, ligands from different coordination spheres are lost

High-K Dielectric Inorganic-Organic Hybrid Thin Films for Field Effect Transistors (FETFT)

The paper discusses the challenges to develop thin films transistors for flexible transparent electronics, displays etc. The sol-gel preparation of hybrid thin films based on dielectric oxides nanoparticles (SiO2 NPs, ZrO2 NPs) and polymethy methacrylate (PMMA) is presented. The high-k hybrid thin films, evaluated as gate dielectric in a MIM structures, were deposed by spin-coating teqhnique. The multilayers (thin films) configuration of MIM structures were investigated by scanning electron microscopy (SEM) and electrical properties. The I-V and C-V curves showed a better dielectric behavior of hybrid films with respect to the simple PMMA films. Dielectric constant values of 2.1, 3.4 and 5.4 have been obtained for PMMA, ZrO2-PMMA and SiO2-PMMA films, respectively