| 摘要 |
PURPOSE:To increase a breakdown strength voltage by providing a region, which is characterized by the same conductive type as that of a source or a drain, a floating potential region, and a low breakdown strength in the vicinity of the source or the drain, to which an external input is applied, on the surface of a semiconductor substrate. CONSTITUTION:A p type source region 6a, a drain region 6b, and a polycrystalline Si gate electrode 4 are provided in the n type Si substrate 1 of the MOS semiconductor device. A floating region 6c with the same conducting type is provided in the vicinity of the drain region 6d, and its breakdown strength is lower than that of the drain region. In this constitution, spread of a depletion layer 9 is prevented, the breakdown strength is increased, and the phenomenon of a lateral transistor is prevented. |
