Semiconductor device with storage node

Claim 1

A semiconductor device, in which a gate transistor is operable to store information in a capacitor formed of a storage node, which is arranged at a crossing between a bit line and a word line, a capacitor insulating film and a cell plate electrode, comprising: a substrate on which a dielectric layer and a semiconductor layer are formed successively; a first impurity diffusion layer of a first conductivity type, which is disposed in said semiconductor layer and contains impurity of a first conductivity type implanted thereto, said first impurity diffusion layer forming one of source/drain regions and forming said bit line; a first interlayer insulating film disposed on said substrate and covering said first impurity diffusion layer; a gate electrode disposed on said first interlayer insulating film, forming also said word line and having upper and lower surfaces; a second interlayer insulating film disposed on said first interlayer insulating film and covering said gate electrode; a contact hole penetrating said first interlayer insulating film, said gate electrode and said second interlayer insulating film and provided for exposing a portion of a surface of said first impurity diffusion layer; a gate insulating film covering a side wall of said contact hole; a first semiconductor layer of the first conductivity type formed in said contact hole, said first semiconductor layer being in contact with the surface of said first impurity diffusion layer and extending from the surface of said first impurity diffusion layer to the substantially same level as said lower surface of said gate electrode; a channel semiconductor layer disposed in said contact hole, said channel semiconductor layer being in contact with a surface of said first semiconductor layer and extending from the surface of said first semiconductor layer to the substantially same level as said upper surface of said gate electrode; a second conductive layer of the first conductivity type disposed on said channel semiconductor layer, said second conductive layer being in contact with a surface of said channel semiconductor layer and forming the other of said source/drain regions as well as said storage node; a capacitor insulating film disposed on said second conductive layer; and a cell plate electrode disposed on said storage node with said capacitor insulating film therebetween.