Semiconductor device and manufacturing method thereof

A semiconductor device comprising:

• a first electrode layer and a second electrode layer;
• a first protective layer provided over the first electrode layer;
• a second protective layer provided over the second electrode layer;
• a first semiconductor layer provided in contact with side face portions of the first electrode layer and the second electrode layer and side face portions and top face portions of the first protective layer and the second protective layer;
• a gate insulating film provided over the first semiconductor layer;
• and
• a gate electrode layer provided to overlap with end portions of the first electrode layer and the second electrode layer via the gate insulating film,
• wherein the first protective layer and the second protective layer have a conductivity that is less than or equal to that of the first semiconductor layer.

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

• forming a gate electrode layer;
• forming a gate insulating film over the gate electrode layer;
• forming a first electrode layer and a second electrode layer over the gate insulating film;
• forming a first protective layer provided over the first electrode layer;
• forming a second protective layer provided over the second electrode layer;
• and
• forming a first semiconductor layer provided to overlap with the gate electrode layer and to be in contact with the gate insulating film, side face portions of the first electrode layer and the second electrode layer, and top face portions and side face portions of the first protective layer and the second protective layer,
• wherein the first protective layer and the second protective layer have a conductivity that is less than or equal to that of the first semiconductor layer.

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

• forming a first electrode layer and a second electrode layer;
• forming a first protective layer provided over the first electrode layer;
• forming a second protective layer provided over the second electrode layer;
• forming a first semiconductor layer provided to be in contact with side face portions of the first electrode layer and the second electrode layer and top face portions and side face portions of the first protective layer and the second protective layer;
• forming a gate insulating film provided over the first semiconductor layer;
• and
• forming a gate electrode layer provided to overlap with end portions of the first electrode layer and the second electrode layer via the gate insulating film,
• wherein the first protective layer and the second protective layer have a conductivity that is less than or equal to that of the first semiconductor layer.