A method of forming an interlayer dielectric film above a metal gate of a metal oxide semiconductor device comprises forming a metal gate above a semiconductor substrate; and forming the interlayer dielectric film above the metal gate by reacting a silicon-containing compound as precursor and a reactant for oxidizing the silicon-containing compound. The silicon-containing compound has the formula: Six(A)y(B)z(C)m(D)n  (I) wherein x is in the range of from 1 to 9; y+z+m+n is in the range of from 4 to 20; and A, B, C, and D independently represent a functional group connecting with a silicon atom. The functional group is selected from a group consisting of alkyl, alkenyl, alkynyl, aryl, alkylaryl, alkoxyl, alkylcarbonyl, carboxyl, alkylcarbonyloxy, amide, amino, alkylcarbonylamino, —NO2, and —CN.