| 摘要 |
PURPOSE:To improve the degree of integration and increase capacitance by elevating impurity concentration in the surface of a semiconductor region between capacitance elements for storing informations by a semiconductor region having a conduction type different from a substrate, raising threshold voltage and shortening a section between the capacitance elements for storing informations. CONSTITUTION:Field insulating films 2 and P-type channel stopper regions 3 are formed to a semiconductor substrate 1, and an insulating film 4 is shaped onto the upper section of the main surface of the semiconductor substrate 1 in a semiconductor-element forming region. When a P-type impurity is introduced to the main surface section of the semiconductor substrate 1 while penetrating the insulating film 4 by using a mask for introducing the im purity, P-type semiconductor region 5 and semiconductor region 6 are shaped. Silicon nitride films and mask-forming layers are laminated on the whole surfaces of the upper sections of the field insulating films 2 and the insulating film 4 in succession, and masks 20 are formed. The silicon nitride films are patterned by employing the masks 20 to each shape insulating films 7A, 7. An N-type impurity and the P-type impurity are induced to the main surface section of the semiconductor region 5 in succession while penetrating the insulating film 4 by using the field insulating films 2 and the masks 20 as masks for introducing the impuri ties. N<+> type semiconductor regions 8A and P-type semiconductor regions 8B are shaped by introducing the impurities. The semiconductor regions 8B are formed in a self-alignment manner to the insulating films 7 shaped between capacitance elements for storing informations, thus shortening a section between the capacitance elements for storing informations. |
