| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce influence of light irradiation effect in a semiconductor element such as a transistor using an oxide semiconductor or a display device using the semiconductor element. <P>SOLUTION: Defects in a band tail level and a band gap are reduced as much as possible, whereby optical absorption of energy in the vicinity of the band gap or less than or equal to the band gap is reduced. In that case, not by merely optimizing the conditions of manufacturing an oxide semiconductor film, but by making an oxide semiconductor be a substantially intrinsic semiconductor or extremely close to an intrinsic semiconductor, defects on which irradiation light acts are reduced and the effect of light irradiation is reduced essentially. That is, even in the case where light with a wavelength of 350 nm is irradiated at 1×10<SP>13</SP>photons/cm<SP>2</SP>sec, a channel region of a transistor is formed using an oxide semiconductor in which an amount of variation in the threshold voltage is less than or equal to 0.65 V, preferably less than or equal to 0.55 V. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
