Deposition and characterization of Si-rich silicon oxide films using HMDS for integrated photonics

Abstract

Silicon-rich silicon oxide (SRSO) films were deposited using thermal-CVD system with organic precursor hexamethyldisilazane (HMDS) and oxygen (O 2) at the temperature range of 760–820 °C. The deposited SRSO films were characterized by using ellipsometry, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX). The effect of deposition temperature on the physical and optical properties of deposited SRSO films has been studied and analyzed. It has been observed that the refractive index (RI) of the deposited films increases while the stress of compressive nature decreases with the corresponding increase in deposition temperature. The peak positions of Si–O–Si stretching bond and the full-width at half maxima (FWHM) of these peaks have been investigated by using FTIR spectroscopy. It was found that the peak position of Si–O–Si stretching bond move toward lower wave number while the corresponding FWHM increases with increase in the deposition temperature. The peak intensities of Si–H, O–H and Si–OH bonds decrease with corresponding increase in deposition temperature, which signifies an improvement in the quality of the deposited SRSO films. The SEM and EDAX analysis clearly reveals the successful deposition of SRSO films with some dense clusters of silicon having size about 500 nm on the surface of the deposited films.