Silicon rich oxide (SRO) is a dielectric material that contains silicon nanoparticles (Si-nps). The composition, structure, and emission of the SRO films deposited by low pressure chemical vapor deposition (LPCVD) were studied; Different microscopic and spectroscopic techniques, such as Atomic Force Microscopy (AFM), High Resolution Transmission Electronic Microscopy and Energy Filtered-TEM (HRTEM and EFTEM), Rutherford Backscattering Spectroscopy (RBS), X-Ray Photoelectrons Spectroscopy (XPS) and Photoluminescence (PL) were used to characterize the SRO films. Results show that SRO films are formed by SiO2, Si-nps, and compounds. The composition, structure (morphology and Si-nps) and luminescence of the SRO films varied with the silicon excess.