| 摘要 |
PURPOSE:To accelerate the operation of an MIS type field effect semiconductor device by nothcing a part of a drain layer and connecting the drain layer via the notched part to a substrate. CONSTITUTION:A linear notched part 10 having a width less than 6mum is formed in a P<-> type well 18 directly under the N<+> type drain 5 of an N-channel FET. A depletion layer 14 is largely expanded from the junction of the well 18 and the substrate 9 toward the substrate side in the N type notched part 10 at the operating time, is completely integrated at the notched part, and becomes a completely pinch- off state. Thus, the thickness and the width of the layer 14 formed at the notched part are remarkably increased, the junction capacity between the drain 5 and the well 18 is decreased at the notched part 10, and can be ignored. Accordingly, the junction capacity of the entirety is reduced in the amount corresponding to the area of the notched part 10, and the operation of the circuit can be accelerated. Since the parasitic junction FET formed in the notched part 10 is completely pinched off so that the drain 5 and the substrate 9 are insulated, no pinch-off current will flow. |
