Leakage reduction in DRAM MIM capacitors

A method for forming a capacitor stack comprising:

• forming a first material on a substrate, wherein the first material is operable as a first electrode of the capacitor stack;
• forming a second material above the first material, wherein the second material is operable as a first dielectric of the capacitor stack, wherein the second material is ZrO2, wherein the second material is lightly doped or non-doped, and wherein the dopant is one of Al, Co, Er, Ga, Gd, Ge, Hf, La, Mg, Si, Sn, Sr, Ti, Y, or combinations thereof;
• forming a third material above the second material, wherein the third material is operable as a second dielectric of the capacitor stack, and wherein the third material has a band gap greater than about 5.8 eV;
• forming a fourth material above the third material, wherein the fourth material is operable as a third dielectric of the capacitor stack, wherein the fourth material is ZrO2,
• wherein the fourth material is highly doped, wherein the dopant is one of Al, Co, Er, Ga, Gd, Ge, Hf, La, Mg, Si, Sn, Sr, Ti, Y, or combinations thereof, and wherein a concentration of the dopant in the fourth material being greater than a concentration of the dopant in the second material;
• and
• forming a fifth material above the fourth material, wherein the fifth material is operable as a second electrode of the capacitor stack.