Re-grown gate structure and fabrication method thereof

A method for fabricating a semiconductor device, the method comprising:

• providing a semiconductor substrate comprising a plurality of fin portions;
• forming a gate dielectric layer on the fin portions, wherein the dielectric layer is conformal to the fin portions;
• forming a first gate electrode layer covering the gate dielectric layer;
• etching the first gate electrode layer to decrease a thickness of the first gate electrode layer;
• and
• forming a second gate electrode layer contacting the first gate electrode layer.

A method for fabricating a semiconductor device, the method comprising:

• providing a semiconductor substrate comprising a plurality of fin portions defining a plurality of first gaps located between the fin portions;
• forming a gate dielectric layer on the fin portions, wherein portions of the gate dielectric layer are formed in the first gaps to define a plurality of second gaps;
• filling the second gaps with a metal material to form a first gate electrode layer on the gate dielectric layer, wherein the first gate electrode layer comprises a plurality of first portions disposed in the second gaps and a second portion on the first portions;
• etching the second portion of the first gate electrode layer to decrease a thickness of the second portion of the first gate electrode layer;
• and
• forming a second gate electrode layer contacting the first gate electrode layer.