Capacitor including a dielectric layer having an inhomogeneous crystalline region and method of fabricating the same
In a capacitor, and a method of fabricating the same, the capacitor includes a lower electrode, a dielectric layer on the lower electrode, and an upper electrode on the dielectric layer, wherein the dielectric layer includes a lower dielectric region contacting the lower electrode, an upper dielectric region contacting the upper electrode, and at least one middle dielectric region between the lower dielectric region and the upper dielectric region, the at least one middle dielectric region having a less crystalline region than both the lower dielectric region and the upper dielectric region.
1. A capacitor, comprising:
a lower electrode;
a dielectric layer on the lower electrode; and
an upper electrode on the dielectric layer,
wherein the dielectric layer includes
a lower dielectric region contacting the lower electrode,
an upper dielectric region contacting the upper electrode, and
at least one middle dielectric region between the lower dielectric region and the upper dielectric region, the at least one middle dielectric region having a less crystalline region than both the lower dielectric region and the upper dielectric region.
2. The capacitor as claimed in claim 1 , wherein the dielectric layer is formed of one or more layers selected from the group consisting of a hafnium oxide layer, an aluminum oxide layer, a tantalum oxide layer, a titanium oxide layer, a zirconium oxide layer, a lanthanum oxide layer, a (Ba x , Sr 1-x )TiO 3 layer, a Pb(Zr, Ti)O 3 layer, and a mixture thereof.
3. The capacitor as claimed in claim 1 , wherein a concentration of impurities in the middle dielectric region is higher than concentrations of impurities in both the lower dielectric region and the upper dielectric region.
4. The capacitor as claimed in claim 1 , wherein the middle dielectric region is formed of an amorphous dielectric layer, and the upper dielectric region and the lower dielectric region are formed of crystalline dielectric layers.
5. The capacitor as claimed in claim 1 , wherein the lower dielectric region, the middle dielectric region, and the upper dielectric region are each formed of a hafnium oxide layer.
6. The capacitor as claimed in claim 5 , wherein a concentration of impurities in the middle dielectric region is higher than concentrations of impurities in both the lower dielectric region and the upper dielectric region.
7. The capacitor as claimed in claim 1 , wherein the lower electrode and the upper electrode are formed of one layer selected from the group consisting of a titanium layer, a titanium nitride layer, a tantalum layer, a tantalum nitride layer, a tungsten layer, a tungsten nitride layer, an aluminum layer, a copper layer, a ruthenium layer, a ruthenium oxide layer, a platinum layer, an iridium layer, an iridium oxide layer, a polysilicon layer, and a mixture thereof.