Chemical vapor deposition method

A chemical vapor deposition method for forming a thin film on a substrate or a wafer, which are arranged in a process chamber, by introducing, in turn, a source gas, a second purge gas, a reactant gas and a first purge gas, the method comprises steps of:

• a) injecting the source gas into the chamber so that the source gas is adsorbed on the substrate;
• b) injecting the second purge gas into the chamber for a predetermined period of time so that the source gas remaining in the chamber is purged;
• c) injecting the reactant gas into a plasma generating portion arranged between a RF electrode plate and a showerhead, said showerhead is electrically grounded, and generating plasma at the plasma generating portion by applying a first-level RF power source to the RF electrode plate so that radical of the reactant gas is adsorbed on the substrate;
• d) injecting the first purge gas into the chamber for a predetermined period of time so that the reactant gas remaining in the chamber is purged;
• e) applying a second-level RF power source to the plasma generating portion at the step a), b) and d) while the steps a) to d) are being repeated;
• and
• wherein an energy level of the second-level RF power source generates radicals whose energy level does not exceed the energy level that the showerhead can reduce to a ground state as the radical passes through the showerhead.