Semiconductor device and a manufacturing method thereof

A semiconductor device, comprising:

• a semiconductor substrate having a main surface;
• a source region and a drain region formed apart from each other in the main surface;
• and
• a gate electrode layer formed over the main surface sandwiched between the source region and the drain region,
• wherein a first recess is formed in the main surface in such a manner as to cross the direction in which the source region and the drain region are opposed to each other, and
• wherein the first recess is disposed between the gate electrode layer and the drain region in plan view.

A method for manufacturing a semiconductor device, comprising the steps of:

• forming a recess in a main surface of a semiconductor substrate;
• forming a lamination structure of a gate electrode layer and a mask layer over a partial region of the recess;
• and
• forming a sidewall insulation film at least over a sidewall of the gate electrode layer of the lamination structure,
• wherein the thickness of the mask layer upon formation of the mask layer is larger than the depth of the recess.

A method for forming a semiconductor device, comprising the steps of:

• forming a recess in a main surface of a semiconductor substrate;
• forming a gate electrode layer over a partial region of the recess;
• and
• forming a sidewall insulation film over a sidewall of the gate electrode layer,
• wherein in the step of forming the sidewall insulation film, the sidewall insulation film is formed with a height equal to or smaller in dimension than the half of the depth of the recess.

A method for manufacturing a semiconductor device, comprising the steps of:

• forming a recess in a main surface of a semiconductor substrate, a first gate electrode layer in a first transistor formation region, and a second gate electrode layer in a second transistor formation region over the main surface;
• forming an insulation film in such a manner as to cover the top of the first gate electrode layer, the top of the second gate electrode layer, and the top of the recess;
• forming a first mask layer in such a manner as to cover portions of the insulation film over the second gate electrode layer and over the recess with the first mask layer, and in such a manner as to expose a portion of the insulation film in the first transistor formation region;
• and
• etching the insulation film in the first transistor formation region with the first mask layer as a mask, and thereby forming a sidewall insulation film including the insulation film over a sidewall of the first gate electrode layer.