Capacitor compatible with high dielectric constant materials having a low contact resistance layer and the method for forming same

A method for fabricating a capacitor having a first and a second electrode, comprising:

• forming an insulative layer overlying a surface;
• forming an opening in the insulative layer to expose a portion of the surface;
• forming a conductive plug in the opening, the conductive plug forming a first portion of the first electrode of the capacitor, the conductive plug recessed below a surface of the insulative layer;
• forming a first conductive layer overlying the conductive plug, the first conductive layer forming a second portion of the first electrode;
• forming a second conductive layer, for preventing diffusion of atoms, in the opening and overlying the first conductive layer such that the second conductive layer is surrounded on sidewalls by the insulative layer, the second conductive layer forming a third portion of the first electrode, the first conductive layer reducing a contact resistance between the conductive plug and the second conductive layer;
• forming a third conductive layer overlying the second conductive layer to form a fourth portion of the first electrode;
• forming a dielectric layer to overlie the third conductive layer, the third conductive layer and the insulative layer substantially preventing oxidation of the second conductive layer;
• and
• forming the second electrode overlying the dielectric layer, the first and the second electrode and the dielectric layer forming the capacitor.

A method for fabricating a capacitor having a first and a second electrode, comprising:

• forming an insulative layer overlying a surface;
• forming an opening in the insulative layer to expose a portion of the surface;
• forming a conductive plug in the opening, the conductive plug forming a first portion of the first electrode of the capacitor, the conductive plug recessed below a surface of the insulative layer;
• forming a first conductive layer overlying the conductive plug, the first conductive layer forming a second portion of the first electrode;
• forming a second conductive layer, for preventing diffusion of atoms, in the opening and overlying the first conductive layer such that the second conductive layer is surrounded on sidewalls by the insulative layer, the second conductive layer forming a third portion of the first electrode, the first conductive layer increasing conductivity between the conductive plug and the second conductive layer;
• forming a third conductive layer overlying the second conductive layer to form a fourth portion of the first electrode;
• forming a dielectric layer to overlie the third conductive layer;
• during forming the dielectric layer, inhibiting oxidation of the second conductive layer using the third conductive layer and the insulative layer;
• and
• forming the second electrode overlying the dielectric layer, the first and the second electrode and the dielectric layer forming the capacitor.

A method for fabricating a capacitor having a first and a second electrode, comprising:

• forming an insulative layer, including an oxide, overlying a substrate surface;
• etching an opening in the insulative layer to expose a portion of the surface;
• forming a polysilicon conductive plug in the opening, the conductive plug forming a first portion of the first electrode of the capacitor, the conductive plug recessed below a surface of the insulative layer;
• forming a first conductive layer overlying the conductive plug, the first conductive layer forming a second portion of the first electrode and including titanium silicide;
• forming a second conductive layer, for preventing diffusion of atoms, in the opening and overlying the first conductive layer such that the second conductive layer is surrounded on sidewalls by the insulative layer, the second conductive layer forming a third portion of the first electrode, the first conductive layer reducing a contact resistance between the conductive plug and the second conductive layer and including titanium nitride;
• forming a platinum, third conductive layer overlying the second conductive layer to form a fourth portion of the first electrode;
• forming a dielectric layer to overlie the third conductive layer, the third conductive layer and the insulative layer substantially preventing oxidation of the second conductive layer, wherein the dielectric layer comprises a dielectric material from a group of materials consisting of BaxSr(1-x) TiO3, BaTiO3, SrTiO3, PbTiO3, Pb(Zr,Ti)O3, (Pb,La)(Zr,Ti)O3, (Pb,La)TiO3, KNO3, and LiNbO3;
• and
• forming the second electrode overlying the dielectric layer, the first and the second electrode and the dielectric layer forming the capacitor.