Method for manufacturing semiconductor device

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

• forming an oxide semiconductor layer over a substrate having a substantially planar surface;
• forming a layer over the oxide semiconductor layer;
• implanting a first oxygen ion in the oxide semiconductor layer through the layer, both top and side surfaces of the oxide semiconductor layer at a singular implantation angle θ so as to provide oxygen in a channel formation region uniformly in a thickness direction of the oxide semiconductor layer;
• and
• performing heat treatment on the oxide semiconductor layer to diffuse an oxygen in the oxide semiconductor layer,
• wherein the implantation angle θ is an angle greater than 10° and less than 85°,
• wherein 0° is an angle which is perpendicular to the substantially planar surface, and
• wherein 90° is an angle which is parallel to the substantially planar surface.

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

• forming an oxide semiconductor layer over a substrate having a substantially planar surface, the oxide semiconductor layer comprising a crystalline oxide semiconductor in which c-axis are aligned perpendicularly to the substantially planar surface;
• implanting a first oxygen ion in the oxide semiconductor layer through both top and side surfaces of the oxide semiconductor layer at a singular implantation angle θ so as to provide oxygen in a channel formation region uniformly in a thickness direction of the oxide semiconductor layer;
• forming a layer over the oxide semiconductor layer;
• and
• performing heat treatment on the oxide semiconductor layer to diffuse an oxygen in a direction perpendicular to a c-axis direction in the oxide semiconductor layer,
• wherein the implantation angle θ is an angle greater than 10° and less than 85°,
• wherein 0° is an angle which is perpendicular to the substantially planar surface, and
• wherein 90° is an angle which is parallel to the substantially planar surface.