OXIDE NITRIDE GATE DIELECTRIC BODY AND FORMING THE SAME

PROBLEM TO BE SOLVED: To provide a method of forming an oxide nitride gate dielectric body in a semiconductor device. SOLUTION: In a method of forming an oxide nitride gate dielectric body 20, first, an oxide nitride layer 22 is formed on the surface of a silicon substrate 12 and then is re-oxidized by a gaseous mixture containing oxygen, and at least one kind of halide to produce an oxide nitride layer whose nitrogen profile is controlled and a silicon dioxide layer 26 formed under the oxide nitride layer. The oxide nitride layer 22 can be formed by putting the surface of the silicon substrate 12 into contact with gas containing nitrogen or oxygen or both of them, at a temperature of 500 deg.C or more or through a chemical vapor deposition method. A re-oxidizing process is performed by heating the silicon substrate 12 in a halide oxide atmosphere containing oxygen and halide, such as HCl, CH2Cl2, C2H3Cl2, C2H2Cl2, CH3Cl, and CHCl3.