Effects of process parameters on the growth of thick SiO2 using plasma enhanced chemical vapor deposition with hexamethyldisilazane

The effects of various deposition parameters such as growth temperature, N2O/HMDS ratio, O2/HMDS ratio, RF power and deposition pressure on the growth characteristics and properties of thick SiO2 film using PECVD are investigated. It is found that a high growth temperature results in a low growth rate and dense films with few visible defects. Excess oxygen flow decreases the growth rate. The growth rate of SiO2 with O2 is lower than that of SiO2 with N2O. As the RF power increases, the growth rate increases and the refractive index approaches that of thermal oxide. As the deposition pressure increases, the growth rate increases first and decreases later. The thickness, etch rate, optical properties and surface roughness of SiO2 were measured using α-step, 6:1 BOE solution, ellipsometry and scanning electron microscope (SEM), respectively.