Methods of implanting ions into different active areas to provide active areas having increased ion concentrations adjacent to isolation structures and devices so formed

摘要

PURPOSE: A method for implanting ions into different active regions with increased ion density adjacent to an isolation structure is provided to prevent a threshold voltage of a transistor from being decreased by an inverse narrow width effect by making the density of ion impurities greater in the first active region of a substrate adjacent to the sidewall of the isolation structure than in the second active region separated from the isolation structure. CONSTITUTION: Ions of the first density are implanted into a gap between the first active region(30) of the substrate(10) adjacent to the isolation structure and a source/drain region(38,39) of an integrated circuit to supply the ions of the first density to the first active region. Ions of the second density are implanted into the first active region and the second active region(32) that is adjacent to the first active region of the substrate and is separated from the isolation structure. The ions of the second density are implanted into the second active region and ions of the first density and the third density greater than the second density are implanted into the first active region.