Method of fabricating a semiconductor memory device
A semiconductor memory device includes a capacitor having a bottom electrode and a top electrode, a dielectric layer between the bottom and top electrodes, and an interface layer between the top electrode and the dielectric layer, the interface layer including a metal oxide and an additional constituent at a grain boundary of the interface layer.
1. A method of fabricating a semiconductor memory device, the method comprising:
providing a substrate having thereon bottom electrodes that are connected to each other through a support pattern;
forming an etch stop layer on the substrate between the bottom electrodes;
forming on the etch stop layer a dielectric layer that continuously extends along surfaces of the bottom electrodes and a surface of the support pattern;
forming on the dielectric layer an upper interface layer that continuously extends along the bottom electrodes and the support pattern; and
forming on the upper interface layer a top electrode that covers the bottom electrodes,
wherein the upper interface layer includes a first metal oxide and a first additional constituent doped into the first metal oxide, the first additional constituent being present at a grain boundary of the first metal oxide.
2. The method as claimed in claim 1 , wherein the first metal oxide includes titanium oxide, and the first additional constituent includes aluminum, silicon, or a combination thereof and has a maximum amount of about 5 at %, based on a total amount of the upper interface layer.
3. The method as claimed in claim 1 , wherein forming the upper interface layer includes:
forming a titanium oxide layer on the dielectric layer; and
doping aluminum into the titanium oxide layer simultaneously with forming the titanium oxide layer.
4. The method as claimed in claim 1 , wherein forming the upper interface layer includes alternately and repeatedly forming a titanium oxide layer and an aluminum-containing layer on the dielectric layer, the aluminum-containing layer includes Al 2 O 3 , AlN, AlC, or any combination thereof.
5. The method as claimed in claim 1 , wherein the etch stop layer and the support pattern each includes a silicon nitride layer.
6. The method as claimed in claim 1 , wherein forming the upper interface layer includes:
forming a titanium oxide layer on the dielectric layer; and
forming an aluminum oxide layer on the titanium oxide layer, such that aluminum of the aluminum oxide layer is doped into the titanium oxide layer.
7. The method as claimed in claim 6 , wherein the aluminum has a uniform concentration in the upper interface layer.
8. The method as claimed in claim 6 , wherein the aluminum has a concentration that gradually decreases as approaching the dielectric layer.
9. The method as claimed in claim 1 , wherein, before forming the dielectric layer, forming a lower interface layer on the bottom electrodes, such that the lower interface layer includes a second metal oxide and a second additional constituent at a grain boundary of the second metal oxide.
10. The method as claimed in claim 9 , wherein the second metal oxide includes titanium oxide, and the second additional constituent includes aluminum, silicon, or a combination thereof at a maximum amount of about 5 at %, based on a total amount of the lower interface layer.
11. A method of fabricating a semiconductor memory device, the method comprising:
providing a substrate having thereon bottom electrodes that are connected to each other through a support pattern;
forming on the bottom electrodes a lower interface layer that continuously extends along surfaces of the bottom electrodes and a surface of the support pattern;
removing a portion of the lower interface layer from the surface of the support pattern, such that the lower interface layer remains on the bottom electrodes;
forming on the lower interface layer a dielectric layer that continuously extends along the surfaces of the bottom electrodes and the surface of the support pattern;
forming on the dielectric layer an upper interface layer that continuously extends along the bottom electrodes and the support pattern; and
forming on the upper interface layer a top electrode that covers the bottom electrodes,
wherein the upper interface layer includes a first titanium oxide and a first additional constituent at a grain boundary of the first titanium oxide, and
wherein the lower interface layer includes a second titanium oxide and a second additional constituent at a grain boundary of the second titanium oxide.
12. The method as claimed in claim 11 , wherein the first additional constituent includes aluminum, silicon, or a combination thereof and has a maximum amount of about 5 at %, based on a total amount of the upper interface layer.
13. The method as claimed in claim 11 ,
wherein the second additional constituent includes aluminum, silicon, or a combination thereof and has a maximum amount of about 5 at %, based on a total amount of the lower interface layer.