Mass density control of carbon films deposited by H-assisted plasma CVD method

In order to obtain high density carbon films with keeping anisotropic deposition profile on trench substrates, we control mass density of carbon films deposited by a H-assisted plasma chemical vapor deposition (CVD) method by ion kinetic energy of ions irradiating on film surface during deposition. The highest mass density of 2.14g/cm³ is obtained for deposition under the ion energy of 75eV and it is 1.4 times as high as that for the ion energy of 32eV. We also have studied etching rate of these films using H₂+N₂ discharge plasmas. The lowest etch rate of 1.8nm/min is obtained for the ion energy of 75eV and it is 2.8 times as low as that for the ion energy of 32eV. Etching rate of carbon films decreases exponentially with increasing the mass density of carbon films. Control of ion energy is the key to obtain high mass density carbon films with keeping anisotropic deposition profile on trench substrates.