Method for fabricating ferroelectric memory device

A method for fabricating a ferroelectric memory device comprising the steps of:

• forming an intermetal insulating layer provided with a contact hole exposing a junction region formed on a semiconductor layer having the junction region;
• forming a contact plug within the contact hole;
• forming successively a barrier layer and a metal layer for storage node electrode on the intermetal insulating layer:
• forming a storage node electrode by patterning the metal layer for storage node electrode and the barrier layer to be contact with the contact plug;
• depositing a ferroelectric layer on the storage node electrode and the intermetal insulating layer at a temperature that the storage node electrode is not oxidized;
• crystallizing the ferroelectric layer;
• heat-treating the crystallized ferroelectric layer, the crystallized ferroelectric layer is performed by UV-O3 treatment at temperature of 200˜400° C. for 1˜30 minutes so as to remove impurities flowed into the ferroelectric layer during depositing the ferroelectric layer and so as to prevent oxygen discrepancy caused by the nitrogen;
• and
• forming a plate electrode on the ferroelectric layer, wherein the storage node electrode is selected from a group consisting of tungsten (W), tungsten nitride (WN), tantalum (Ta), tantalum nitride (TaN), titanium (Ti), and Titanium nitride (TiN.),
• wherein the ferroelectric layer is deposited at temperature of 100˜400° C. according to the MOCVD method.