Synthesis And Modification Of Polymer Dielectric Thin Films By Chemical Vapor Deposition

Polymer dielectric thin film materials are widely used in capacitive energy storage,smart sensing.5G communication substrates,flexible devices and other fields due to their good insulation,flexibility and processability.With the continuous improvement of device integration density and material processing accuracy requirements,it is an important direction to develop new nanofabrication methods for polymer dielectric thin films,and to realize the regulation of film thickness and microscopic composition.On the one hand,in the fields of chip manufacturing,chip packaging,and optical chip manufacturing,there is a major demand in conformally depositing dielectric thin film materials on nanostructures with extreme aspect ratios and complex shapes,and obtaining precise film thickness control at the sub-nanometer scale.On the other hand,the regulation of the composition of the polymer dielectric film at the microscopic scale through gas phase processing can endow it with an improvement in dielectric constant,breakdown resistance,etch resistance and mechanical properties of the materials.A new method of plasma-enhanced initiated molecular layer deposition(PE-iMLD)was established in this dissertation to meet the needs of film thickness control in polymer thin film nanofabrication.The optimal deposition conditions were established by exploring important parameters such as plasma power,reactant pulse duration,and inert gas purge duration.PE-iMLD overcomes the problem of solvent residue in traditional wet-chemistry methods of film fabrication,can obtain sub-nanometer film thickness control unmatched by initiated chemical vapor deposition(iCVD),and has good compatibility with existing integrated circuit equipment.Aiming at the requirement of controlling the microscopic composition of polymer dielectric thin film materials,this dissertation established vapor phase infiltration(VPI)doping technology for the modification of polyvinylidene fluoride(PVDF)thin film materials.Realizing the molecular level dispersion of ZnO,TiO2 inorganic components,the nanoscale PVDF-based composite thin film materials were obtained.We found that VPI ZnO modification can significantly reduce dielectric loss of PVDF,thereby enhancing energy storage efficiency.VPI TiO2 modification can increase dielectric constant and breakdown field strength of the films at the same time,so as to obtain higher energy storage density(up to 9.02 J/cm3)than pristine PVDF.