| 摘要 |
PURPOSE:To reduce a threshold voltage Vth with a sharp rise by channel-doping it before a gate electrode is formed to form a light P-type polycrystalline silicon. CONSTITUTION:After an island 1-2 of an undoped polycrystalline silicon thin film is formed on an insulating transparent substrate 1-1, boron of P-type impurity is channel-implanted to the polycrystalline silicon to form a light P-type polycrystalline silicon. Then, after a gate oxide film 1-4, a gate electrode 105 are formed, it is conducted in a hydrogen plasma processing step, a hydrogen ion implanting step or a plasma nitride film forming step. Thus, a CMOS polycrystalline silicon thin film transistor having excellent characteristics in which the rise of a subthreshold region becomes sharp, the absolute value of Vth is reduced, the magnitudes of the absolute values of Vth of N-channel and P-channel coincide can be performed. |
