Ferroelectric memory devices

Abstract

Forming a ferroelectric memory device can include forming an insulating layer on a substrate, forming a sacrificial layer on the first insulating layer so that the insulating layer is between the sacrificial layer and the substrate, and forming a contact hole extending through the sacrificial layer and the insulating layer. A conductive contact plug can be formed in the contact hole. After forming the conductive contact plug in the contact hole, the sacrificial layer can be removed so that the conductive contact plug extends beyond the insulating layer, and so that sidewalls of the conductive contact plug extending beyond the insulating layer are exposed. A first electrode can be formed on exposed portions of the conductive contact plug, a ferroelectric layer can be formed on the first electrode, and a second electrode can be formed on the ferroelectric layer such that the ferroelectric layer is between the first and second electrodes. Related structures are also discussed.

1 . A ferroelectric memory device comprising: 
 an insulating layer on a substrate including a contact hole extending therethrough;    a conductive contact plug in the contact hole wherein the conductive contact plug extends beyond the insulating layer so that sidewalls of the conductive contact plug extending beyond the insulating layer are exposed wherein a width of portions of the conductive contact plug extending beyond the insulating layer is greater than a width of portions of the conductive contact plug extending through the insulating layer;    a first electrode on exposed portions of the conductive contact plug;    a ferroelectric layer on the first electrode; and    a second electrode on the ferroelectric layer such that the ferroelectric layer is between the first and second electrodes.    
   
   
       2 . A ferroelectric memory device according to  claim 1  wherein the first, electrode, the ferroelectric layer, and the second electrode extend onto the insulating layer and wherein the ferroelectric layer and the second electrode do not extend beyond the first electrode.  
   
   
       3 . A ferroelectric memory device according to  claim 1  wherein the ferroelectric layer and the second electrode extend across the first insulating layer beyond the first electrode.  
   
   
       4 . A ferroelectric memory device according to  claim 3  wherein the insulating layer further includes a second contact hole extending therethrough, the ferroelectric memory device further comprising: 
 a second conductive contact plug in the second contact hole; and    a third electrode on exposed portions of the second conductive contact plug wherein the first and third electrodes are separate electrodes wherein the ferroelectric layer extends from the first electrode to the third electrode.    
   
   
       5 . A ferroelectric memory device according to  claim 1  further comprising: 
 an etch stop layer on the insulating layer wherein the contact hole extends through the etch stop layer.    
   
   
       6 . A ferroelectric memory device according to  claim 5  wherein the etch stop layer comprises a material selected from the group consisting of silicon nitride, silicon nitride oxide, titanium oxide, titanium nitride, and titanium aluminum nitride.  
   
   
       7 . A ferroelectric memory device, comprising: 
 a substrate where a conductive region is formed;    an interlayer insulating layer stacked on the substrate, the interlayer insulating layer having a contact hole exposing the conductive region;    a contact plug filling the contact hole, the contact plug having a projection that is higher than the interlayer insulating layer; and    a capacitor including a lower electrode, a ferroelectric layer pattern, and an upper electrode that sequentially cover the projection of the contact plug,    wherein a width of the projection is greater than that of the contact hole.    
   
   
       8 . The device as claimed in  claim 7 , wherein a width of the lower electrode is greater than that of the projection of the contact plug.  
   
   
       9 . The device as claimed in  claim 7 , further comprising an etch stop layer formed on the interlayer insulating layer.  
   
   
       10 . The device as claimed in  claim 9 , wherein the etch stop layer is one selected from the group consisting of a silicon nitride layer, a silicon nitride oxide layer, a titanium oxide layer, a titanium nitride layer, a double layer of a titanium nitride layer/a titanium layer, and a titanium aluminum nitride layer.