Method of forming twin doped regions of the same depth by high energy implant

A process for producing a semiconductor device comprising the steps of:

• implanting first conductivity type impurity ions all over a region of a workpiece where impurity ions are to be implanted;
• forming a mask having an opening on said workpiece;
• implanting impurity ions of second conductivity type opposite to said first conductivity type in such a dose as to reduce the concentrations of said first and second conductivity type impurity ions to substantially zero at the edge of said opening through said opening;
• and annealing the resulting workpiece to form first and second conductivity type regions in a region covered with said mask and a region corresponding to said opening, respectively.

A process for producing a semiconductor device comprising the steps of:

• implanting first conductivity type impurity ions at a predetermined depth all over a region of a workpiece where impurity ions are to be implanted;
• forming a trench extending from the surface of the workpiece, and forming an insulation material in said trench so as to form a trench isolation structure;
• forming a mask having an edge forming an opening on said workpiece, said mask being formed such that the edge thereof forming the opening is positioned over the trench;
• implanting impurity ions of second conductivity type opposite to said first conductivity type in a dose about twice as large as that of said first conductivity type impurity ions at substantially the same depth as in the step of ion implantation of said first conductivity type impurity ions through said opening;
• and annealing the resulting workpiece to form first and second conductivity type regions in a region covered with said mask and a region corresponding to said opening, respectively, whereby the first and second conductivity type regions are spaced from each other by the trench isolation structure.