Preparation of phenylsilsesquioxane films from phenylsilsesquiazane possessing Si-N backbones

Phenylsilsesquiazane (PhSSz) prepared by ammonolysis of phenyltrichlorosilane was spin-coated on Si(100) substrates. The resulting PhSSz films were subsequently converted into phenylsilsesquioxane films via hydrolysis in an autoclave under various hydrothermal conditions. IR spectroscopy revealed that the relative intensities of Si-N-Si and N-H stretching bands decreased, while a Si-O-Si stretching band appeared. Upon heating at 160 °C for 72 h with 0.5 mL of water, PhSSz was completely converted into phenylsilsesquioxane. Another poysiloxane film was obtained from a polysilazane prepared by ammonolysis of a mixture of phenyltrichlorosilane and trichlorosilane (PhHSSz). FE-SEM and AFM observations revealed that the phenylsilsesquioxane film and the poysiloxane film had dense structures and smooth surfaces.