Patent attributes
After an ONO film in which a silicon nitride film (22) formed by a plasma nitriding method using a plasma processor having a radial line slot antenna is sandwiched by silicon oxide films (21), (23), a bit line diffusion layer (17) is formed in a memory cell array region (11) by an ion implantation as a resist pattern (16) taken as a mask, then lattice defects are given to the silicon nitride film (22) by a further ion implantation. Accordingly, a highly reliable semiconductor memory device can be realized, in which a high quality nitride film is formed in a low temperature condition, in addition, the nitride film can be used as a charge trap film having a charge capture function sufficiently adaptable for a miniaturization and a high integration which are recent demands.