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. (C) 2000 Elsevier Science S.A. All rights reserved.