FeRAM (ferroelectric random access memory) and method for forming the same

A ferroelectric random access memory (FeRAM) device comprising:

• a semiconductor substrate;
• a transistor having a gate insulating film, a gate electrode and a source/drain region that are formed in the semiconductor substrate;
• a first interlayer insulating film formed over the transistor;
• a plug buried in a contact hole exposing the source/drain region of the transistor through a selective etching process of the first interlayer insulating film;
• an oxidation barrier film formed on the plug and on the first interlayer insulating film;
• an aluminum oxide (Al2O3) oxidation barrier film formed on sidewalls of the oxidation barrier film and a portion of the first interlayer insulating film in order to prevent oxygen from diffusion into an interface between the aluminum oxide (Al2O3) oxidation barrier film and the interlayer insulating film;
• a silicon nitride (Si3N4) oxidation barrier film formed on the aluminum oxide (Al2O3) oxidation barrier film;
• a bottom electrode formed on the aluminum oxide (Al2O3) oxidation barrier film and the silicon nitride (Si3N4) oxidation barrier film;
• a ferroelectric thin film formed on the bottom electrode;
• and
• a top electrode formed on the ferroelectric thin film.

A method for fabrication a ferroelectric random access memory (FeRAM), comprising the steps of:

• a) forming a semiconductor substrate;
• b) forming a transistor having a gate insulating film, a gate electrode and a source/drain region that are formed in the semiconductor substrate;
• c) forming a first interlayer insulating film over the transistor;
• d) burying a plug in a contact hole exposing the source/drain region of the transistor through a selective etching process of the first interlayer insulating film;
• e) forming a first oxidation barrier film on the plug and the first interlayer insulating film;
• f) forming a lateral oxidation barrier film on sidewalls of the first oxidation barrier film and on a portion of the first interlayer insulating film in order to prevent oxygen from diffusing into an interface therebetween, wherein the lateral oxidation barrier film includes a second oxidation barrier film on sidewalls of the first oxidation barrier film and on a portion of the first interlayer insulating film, and a third oxidation barrier film on the second oxidation barrier film;
• g) forming a bottom electrode on the first oxidation barrier film and the lateral oxidation barrier film;
• h) forming a ferroelectric thin film on the bottom electrode;
• and
• j) forming a top electrode on the ferroelectric thin film.

A method for fabrication a ferroelectric random access memory (FeRAM), comprising steps of:

• forming a semiconductor substrate;
• forming a transistor having a gate insulating film, a gate electrode and a source/drain region that are formed in the semiconductor substrate;
• forming a first interlayer insulating film over the transistor;
• burying a plug in a contact hole exposing the source/drain region of the transistor through a selective etching process of the first interlayer insulating film;
• forming an oxidation barrier film on the plug and on the first interlayer insulating film;
• forming an aluminum oxide (Al2O3) oxidation barrier film on sidewalls of the oxidation barrier film and on a portion of the first interlayer insulating film to be contacted each other in order to prevent oxygen from diffusion into an interface between the aluminum oxide (Al2O3) oxidation barrier film and the interlayer insulating film;
• forming a silicon nitride (Si3N4) oxidation barrier film on the aluminum oxide (Al2O3) oxidation barrier film;
• forming a bottom electrode on the oxidation barrier film, the aluminum oxide oxidation barrier film and the silicon nitride oxidation barrier film;
• forming a ferroelectric film on the bottom electrode;
• forming a top electrode on the ferroelectric film;
• and
• forming a second interlayer insulating film on the entire structure.