Method of depositing dielectric film having Si-N bonds by modified peald method

A method of forming a dielectric film having Si—N bonds on a semiconductor substrate by plasma enhanced atomic layer deposition (PEALD), which comprises:nselecting a combination of gases for forming a dielectric film having Si—N bonds by PEALD, said gases comprising a reactive gas, a rare gas, and a Si-containing precursor, which are different from each other;continuously introducing the reactive gas and the rare gas without interruption into a reaction space inside which the semiconductor substrate is placed;introducing the precursor in pulses into the reaction space;exciting an RF plasma in pulses in the reaction space, wherein each pulse of exciting the RF plasma starts immediately after each pulse of introducing the precursor, wherein one cycle is defined by one pulse of introducing the precursor with no pulse of exciting the RF plasma as a first period, one pulse of exciting the RF plasma with no pulse of introducing the precursor as a second period, and no pulse of introducing the precursor and no pulse of exciting the RF plasma as a third period; andforming a dielectric film having Si—N bonds on the substrate by repeating the cycle multiple times.