| 摘要 |
PURPOSE:To provide a high breakdown strength between a source and a drain and to simultaneously obtain high mutual conductance in a polycrystalline silicon thin film transistor by providing offset gate regions between a gate and a source, and between the gate and a drain, and setting the impurity concentrations of the offset gate regions to a specific range. CONSTITUTION:Offset gate regions 8 are provided between a gate 4 and a source 5 and between the gate 4 and a drain 6 of a polycrystalline silicon thin film transistor in which a polycrystalline silicon thin film 2 is used as a channel region. The impurity concentrations of the regions 8 are set to 8 X 10<16> cm<-3> or higher and smaller than the impurity concentration of the regions 5, 6. For instance, P is implanted by an ion implanting method 1.5 X 10<17> cm<-3> to the offset gate region of the film 2 on a quartz substrate 1 and heat treated at 900 deg.C in a nitrogen atmosphere to be activated. Thereafter, in order to form the regions 5, 6, As is added 10<20> cm<-3> by an ion implanting method and heat treated at 900 deg.C in a nitrogen atmosphere to be activated. |
