Effect of the very high frequency plasma with a balanced power feeding on silicon film deposition

Characteristics of very high frequency plasma produced by a balanced power feeding method were experimentally and numerically investigated by comparison with those of a conventional power feeding method. The measurement results of the plasma parameters in H2 or SiH4/H2 plasma showed that the electron density was a few times higher and the gas pressure at which the plasma was stably sustained was much higher than that in the conventional power feeding. In addition, the electron temperature and the sheath potential near a substrate were lower by about 30%. The numerical simulation in accordance with the experimental condition suggested that the completely floating electrodes cause the decrease of the sheath potential. These characteristics of the plasma parameters seem to be effective for the decrease of ion bombardment damage. As a result of the microcrystalline silicon thin film fabrication, it was showed that the defect density in the balanced power feeding was lower.