Highly transparent silicon carbon nitride (SiCN) films were prepared by hot wire chemical vapor deposition (HWCVD) at low temperature as low as 40oC. Hexamethyldisilazane (HMDS) and NH3 were used as the source materials for SiCN deposition. The SiCN film prepared by only HMDS was completely transparent in the wavelength of the visible region. Moreover, there was a little absorption in the ultraviolet region. However, SiCN prepared by using HMDS and NH3 showed almost transparent both visible and UV regions.