Rare earth doped Lu2SiO5 thin films have been prepared by combining sol-gel process and spin coating. Annealing treatment results in the crystallization of the film and efficient incorporation of rare earth doping ions. XPS and RBS spectrocopies showed that the composition of the films is close to the nominal one. Adventitious carbon has been observed and attributed to incomplete pyrolysis of metal-organic precursors. XPS concentrations profiles show a good homogeneity for the films. RBS demonstrated some inter-diffusion between amorphous carbon substrate and silicate films resulting in a gradient of carbon at the interface between the substrate and the film itself.