Treatment of electrodes of MIM capacitors
A method includes forming a first electrode, and depositing a dielectric layer over the first electrode. The dielectric layer has a first dielectric constant and a first thickness. A dielectric capping layer is deposited over the dielectric layer. The dielectric capping layer has a second dielectric constant higher than the first dielectric constant, and a second thickness smaller than the first thickness. The method further includes forming a second electrode over the dielectric capping layer, forming a first contact plug electrically connecting to the first electrode, and forming a second contact plug electrically connecting to the second electrode.
1 . A method comprising:
forming a first electrode;
depositing a dielectric layer over the first electrode, wherein the dielectric layer has a first dielectric constant and a first thickness, and wherein the dielectric layer is deposited over and contacting a native oxide layer of the first electrode;
depositing a dielectric capping layer over the dielectric layer, wherein the dielectric capping layer has a second dielectric constant higher than the first dielectric constant, and the dielectric capping layer has a second thickness smaller than the first thickness;
forming a second electrode over the dielectric capping layer;
forming a first contact plug electrically connecting to the first electrode; and
forming a second contact plug electrically connecting to the second electrode.
2 . The method of claim 1 , wherein the depositing the dielectric capping layer comprises depositing a first titanium oxide layer.
3 . The method of claim 2 , wherein a second titanium oxide layer is formed over the first electrode and under the dielectric layer.
4 . The method of claim 3 , wherein the second titanium oxide layer is formed through processes that comprise a deposition process.
5 . The method of claim 3 , wherein the first titanium oxide layer and the second titanium oxide layer have a same thickness.
6 . The method of claim 1 , wherein the native oxide layer comprises a first titanium oxide layer.
7 . The method of claim 6 further comprising depositing a second titanium oxide layer over the first titanium oxide layer, wherein the second titanium oxide layer is under the dielectric layer.
8 . The method of claim 6 , wherein the first electrode comprises titanium nitride, and wherein the first titanium oxide layer comprises nitrogen doped therein.
9 . The method of claim 1 further comprising:
performing a plasma treatment on the first electrode using a process gas comprising nitrogen (N 2 ).
10 . The method of claim 1 , wherein the first contact plug and the second contact plug are in a polymer layer.
11 . A structure comprising:
a capacitor comprising:
a first electrode;
a major capacitor insulator over the first electrode, wherein the major capacitor insulator comprises hafnium zirconium oxide, wherein the major capacitor insulator has a first dielectric constant and a first thickness;
a dielectric capping layer over the major capacitor insulator, wherein the dielectric capping layer comprises titanium oxide, and wherein the dielectric capping layer has a second dielectric constant higher than the first dielectric constant, and the dielectric capping layer further has a second thickness smaller than the first thickness; and
a second electrode over the dielectric capping layer.
12 . The structure of claim 11 further comprising an additional dielectric layer underlying and contacting the major capacitor insulator, wherein the additional dielectric layer comprises titanium oxide.
13 . The structure of claim 12 , wherein the additional dielectric layer further comprises nitrogen doped in the titanium oxide.
14 . The structure of claim 12 , wherein the dielectric capping layer and the additional dielectric layer have a same thickness.
15 . The structure of claim 12 , wherein the additional dielectric layer comprises a sidewall portion extending on a sidewall of the first electrode.
16 . The structure of claim 12 , wherein the additional dielectric layer is free from a sidewall portion extending on a sidewall of the first electrode.
17 . The structure of claim 11 further comprising a polymer layer, wherein the capacitor is formed in the polymer layer.
18 . A structure comprising:
a first electrode comprising titanium nitride;
a capacitor insulator comprising:
a titanium oxynitride layer over the first electrode;
a dielectric layer over the titanium oxynitride layer; and
a titanium oxide layer over the dielectric layer;
a second electrode over the capacitor insulator, wherein the second electrode comprises titanium nitride;
a first contact plug electrically connecting to the first electrode; and
a second contact plug electrically connecting to the second electrode.
19 . The structure of claim 18 , wherein the dielectric layer is thicker than both of the titanium oxynitride layer and the titanium oxide layer.
20 . The structure of claim 18 , wherein dielectric constants of the titanium oxynitride layer and the titanium oxide layer are higher than an additional dielectric constant of the dielectric layer.