The application of titanium dioxide (TiO2) films as a phosphorus diffusion barrier is investigated. The purpose is to study the possibility of using TiO2 to replace thermally grown silicon dioxide (SiO 2) as a phosphorus diffusion barrier to allow the formation of a selective emitter in the buried contact (BC) solar cell processing. The TiO 2 films are deposited on silicon wafers at 450°C before phosphorus (POCl3) diffusion. The result shows that TiO2 is a potential diffusion barrier, as the resistivity under the masked regions is as high as 800 Omega;?/sq. However, the scanning electron microscopic (SEM) images reveal that there is a significant change in surface morphology of the films when phosphorus is involved in the process. This morphology change compared to other sintering gases is also discussed.