| 摘要 |
PURPOSE:To increase mutual conductance without spreading the area of a gate and augmenting the capacitance of an input gate, and to lower noises by forming a transistor, impurity distribution of which under the gate is not equalized, on a head section for an output means. CONSTITUTION:A first P-type well 5, an N<-> semiconductor layer 6 and a second P-type well are shaped onto an N-type substrate 4 in succession, repeating ion implantation and impurity diffusion. Since a second P-type semiconductor layer 7 is extended from the source 25 side, impurity diffusion under a gate 27 is not equalized, and threshold voltage on the source 25 side is made larger than that on the drain 26 side. Accordingly, the mutual conductance of the transistor can be augmented without remarkably increasing the area of the gate 27, input capacitance, and noises are reduced. |
