Technique for manufacturing semiconductor devices comprising transistors with different threshold voltages

A method, comprising:

• forming a first gate electrode structure on a first semiconductor region;
• forming a second gate electrode structure on a second semiconductor region;
• forming a third gate electrode structure on a third semiconductor region;
• performing a first implantation sequence comprising at least a source and drain extension implantation and a first halo implantation in said first, second and third semiconductor regions;
• forming a first resist mask above said first semiconductor region;
• performing a second implantation sequence comprising at least a second halo implantation in said second and third semiconductor regions;
• removing said first resist mask;
• forming a second resist mask above said first and second semiconductor regions;
• performing a third implantation sequence comprising at least a third halo implantation in said third semiconductor region;
• and
• removing said second resist mask.

A method, comprising:

• providing a first semiconductor region and a second semiconductor region;
• performing a first implantation sequence implanting a first dose of an ion species in said first and second semiconductor regions;
• forming a mask above said first semiconductor region;
• and
• performing a second implantation sequence implanting a second dose of said ion species in said second semiconductor region while said first semiconductor region is covered by said mask.