Patent ID: 6773985
Filing Date: 2004-08-10
Classification: H01L

Abstract:
A method for forming DRAM cell, comprising the steps of:forming a buried layer by implanting a high concentration impurity into a semiconductor substrate; forming a MOS transistor having a first gate oxide film, a first gate electrode, a source and drain region; forming a planarized first interlayer insulating film on the entire surface; etching a portion of the first interlayer insulating film on the drain region, the drain region, and a portion of the semiconductor substrate below the drain region to expose the buried layer, whereby forming a contact hole for storage electrode; forming a vertical MOS transistor in the contact hole by forming a second gate oxide film pattern whose both ends are respectively overlapped on the drain region and a second gate electrode overlapped on the second gate oxide film; forming a storage electrode on the second gate electrode so that the both ends are respectively extending on the drain region; forming a dielectric layer and a plate electrode on the storage electrode; forming a planarized second interlayer insulating film on the entire surface; sequentially etching the second interlayer insulating film and the first interlayer insulating film on the source region to expose the source region, whereby forming a bit line contact hole; and forming a bit line contacting the source region through bit line contact hole.