| 摘要 |
PROBLEM TO BE SOLVED: To provide an oxide semiconductor material which imparts good reliability to a transistor.SOLUTION: A formula (&sgr;=4&pgr;*nk*E*&egr;/h) for determining optical conductivity &sgr; is derived with a formula representing the imaginary part &egr;of complex dielectric constant and a formula representing light energy E. Here, &egr;is the vacuum permittivity, h is Planck constant, and &pgr; is the ratio of the circumference of a circle to its diameter, and the optical conductivity &sgr; is calculated using extinction coefficient k and refractive index n of an oxide semiconductor film measured with an optical measuring instrument. A semiconductor device is manufactured using an oxide semiconductor film in which the optical conductivity &sgr;, when irradiated with the light of energy 4 eV, is 410 &OHgr;cmor less. |
