Semiconductor device and method for manufacturing the same

A semiconductor device comprising:

• an oxide semiconductor film comprising:
• a first region;
• a pair of second regions, the first region located between the pair of second regions;
• and
• a pair of third regions, the first region and the pair of second regions located between the pair of third regions;
• a gate insulating film over the oxide semiconductor film;
• a first electrode over the gate insulating film and overlapping with the first region;
• and
• a first sidewall insulating film and a second sidewall insulating film located on side surfaces of the first electrode,
• wherein the first sidewall insulating film overlaps with one of the pair of second regions, and the second sidewall insulating film overlaps with the other of the pair of second regions,
• wherein the first region is a c-axis aligned crystalline oxide semiconductor region,
• wherein each of the pair of second regions and the pair of third regions is an amorphous oxide semiconductor region comprising a dopant,
• wherein a dopant concentration of the pair of third regions is higher than a dopant concentration of the pair of second regions, and
• wherein the gate insulating film overlaps with the pair of third regions.

A semiconductor device comprising:

• an oxide semiconductor film comprising:
• a first region;
• a pair of second regions, the first region located between the pair of second regions;
• and
• a pair of third regions, the first region and the pair of second regions located between the pair of third regions;
• a gate insulating film over the oxide semiconductor film;
• and
• a first electrode over the gate insulating film and overlapping with the first region,
• wherein the first region comprises crystals of which a c-axis is substantially aligned in a direction perpendicular to a surface of the first region,
• wherein each of the pair of second regions and the pair of third regions is an amorphous oxide semiconductor region comprising a dopant,
• wherein a dopant concentration of the pair of third regions is higher than a dopant concentration of the pair of second regions, and
• wherein the gate insulating film overlaps with the pair of third regions.