| 摘要 |
PURPOSE:To prevent the variation in threshold voltage and the degradation of gm by preparing a second electrode buried in a second groove coated with gate insulation and a third electrode which is formed on at least one side of an opening in the second groove and forms a second rectifying junction in cooperation with a semiconductor substrate. CONSTITUTION:At the bottom of a groove 9, an n<+> polysilicon 3 and a substrate 1 are in contact to form an n<+> layer 2 on the substrate. The electrode groove 9 is adjacent to a gate groove 10 in which a polysilicon gate electrode 6 is buried. The gate groove 10 is connected to an n<+> polysilicon 8. A p-n junction is formed between the n<+> polysilicon 8 and a substrate 1 by diffusion from the polisilicon 8 and the substrate. The n<+> layer 2 serves as a source-drain region. For external connection of the n<+> polysilicon 3, the electrode groove 9 is extended outside the MOSFET and connected to an interconnection layer on a surface oxide layer through an opening provided in the surface oxide layer. |
