A high density CMOS dynamic RAM cell comprising a transistor and capacitance means formed in an n-well is disclosed. The capacitance means includes a polysilicon plate member disposed above a p-type region formed in the n-well. A buried contact, extending from the plate member, pierces the p-type region and contacts the well. In addition to the capacitance associated with the plate member, p-type region and well, capacitance is obtained between the side walls of the n-type regions and p-type regions.