Ferroelectrics/insulator/silicon structures were prepared using (Y,Yb)MnO3 films as ferroelectrics and HfO2 layers as insulator though the alkoxy-derived precursor solutions. Although the HfO2 layer was downsized to reduce operating voltage, good properties had not been obtained because of the disordered interface. To solve this problem, process time was reduced and the effects of the crystallization conditions of Y0.5Yb0.5MnO3 films on 5-nm-thick HfO2 layer were investigated. The crystallization in each deposition layer was considered necessary in obtaining a single phase of hexagonal (Y,Yb)MnO3. The preparation of the Y0.5Yb0.5MnO3 films using a diluted solution was effective in improving crystallinity and the degree of c-axis orientation. The leakage current density should be reduced by the improvement of the interface structure in the Y0.5Yb0.5MnO3 films on the 5-nm-thick HfO2 layer.