Enhancement of removing OH bonds from low-temperature deposited silicon oxide films by adding water vapor into NH3 gas annealing at 130 oC

Abstract It was found that annealing with water-vapor-added NH 3 gas (water-added NH 3 ) is more effective than with dry NH 3 at removing residual OH bonds in silicon oxide (SiOx) films deposited by atmospheric chemical vapor deposition with an organic silicon source. Fourier transform infrared spectra showed that reduction amount of OH bonds using the water-added NH 3 was ~4 or ~1.3 times larger than using the conventional dry N 2 or dry NH 3 mixed with N 2 gas without water, respectively. This result is something strange because water can be a potential candidate of OH sources. The effect of water vapor on OH-bond removal can be explained by considering following three factors. One is that low-temperature SiOx films are constrained somewhat, the second is that strained Si-O-Si bonds are in higher or more unstable energy state than strain-free ones, and the third is that highly strained bonds are easily hydroxylated to form Si-OH bonds.