| 摘要 |
PURPOSE:To prevent a punch through between memory cells by providing a groove formed in an element separating region to a high density substrate, diffusing the same conductive type impurity as the substrate in the groove, and forming the groove of the memory the same as the groove. CONSTITUTION:Grooves are formed in a semiconductor substrate having the same conductive type low density layer 202 as a P type high density silicon substrate 201 on the substrate 201, polycrystalline silicons (208a, 208b) are buried through an insulating film, and memory capacitance elements (212a, 212b) are formed. A polycrystalline silicon 203 containing the same conductive type impurity as the substrate is buried in the first groove formed under the thick field insulating film 205 separated between the elements to form a high impurity density field inversion preventive region. The depth of the first groove is equal to or deeper than the layer 202. |
