SEMICONDUCTOR STORAGE DEVICE

摘要

PURPOSE:To realize a high integrity by a method wherein a hole-filling type vertical transistor is formed in a semiconductor substrate and a drain to which an independent potential is applied is confined in the bottom of the hole and an element isolation region is eliminated. CONSTITUTION:A hole 10 whose diameter is larger at the bottom than at the opening is provided in a P-type substrate 1 and an electrically isolated 1st gate electrode 3 is formed on the side wall of the hole 10 with a gate oxide film 2 in-between. A 2nd gate electrode 5 facing the electrode 3 is provided with a 2nd gate oxide film 4 in-between and a metal wiring layer 9 which is brought into contact with a drain layer 6 at the bottom of the hole 10 and with a source layer 7 on the surface of the substrate 1 is also provided. With this constitution, a transistor in which the side wall of the hole 10 is used as a channel region 11 is formed and the electrode 3 functions as a floating gate into which hot carriers produced directly below the channel region are injected and the electrode 5 functions as a control gate.