Semiconductor device and method for manufacturing the same

A method for manufacturing a semiconductor device comprising steps of:

• forming an oxide semiconductor layer containing In, Ga, and Zn so that the oxide semiconductor layer comprises a crystal region comprising a crystal;
• and
• forming a conductive layer containing copper over the oxide semiconductor layer,
• wherein the crystal is represented by InGaZnO4,
• wherein each of an In content, a Ga content, and a Zinc content in the oxide semiconductor layer is identified by inductively coupled plasma mass spectrometry,
• wherein the Zn content is less than the In content and the Ga content, and
• wherein the Ga content is less than the In content.

A method for manufacturing a semiconductor device comprising steps of:

• forming an oxide semiconductor layer containing In, Ga, and Zn so that the oxide semiconductor layer comprises a crystal region comprising a crystal;
• and
• forming a conductive layer containing copper over the oxide semiconductor layer,
• wherein the crystal is represented by InGaZnO4,
• wherein each of an In content, a Ga content, and a Zinc content in the oxide semiconductor layer is identified by Rutherford backscattering spectrometry,
• wherein the Zn content is less than the In content and the Ga content, and
• wherein the Ga content is less than the In content.