Leakage reduction in DRAM MIM capacitors
AssigneesIntermolecular, Inc., Elpidia Memory, Inc.
InventorsTony P. Chiang, Wim Y. Deweerd, Sandra G Malhotra
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Abstract
A method for forming a DRAM MIM capacitor stack having low leakage current involves the use of a first electrode that serves as a template for promoting the high-k phase of a subsequently deposited dielectric layer. The high-k dielectric layer includes a doped material that can be crystallized after a subsequent annealing treatment. An amorphous blocking is formed on the dielectric layer. The thickness of the blocking layer is chosen such that the blocking layer remains amorphous after a subsequent annealing treatment. A second electrode layer compatible with the blocking layer is formed on the blocking layer.
Claims20
A method for forming a capacitor stack, the method comprising:
- forming a first layer on a substrate,
- wherein the first layer is operable as an electrode;
- forming a second layer on the first layer,
- wherein the second layer comprises a dielectric material, and
- wherein the second layer further comprises a dopant;
- forming a third layer on the second layer,
- wherein the third layer is operable as a blocking layer,
- wherein the third layer comprises a ternary metal oxide, and
- wherein the k value of the third layer is between 20 and 50 and the band gap of the third layer is greater than 4.8 eV;
- after forming the third layer, annealing the first layer, the second layer, and the third layer at a temperature of between about 300 C and 600 C in an oxidizing atmosphere including between about 0% O2 and 20% O2,
- wherein the second layer is crystalline after annealing,
- wherein the third layer is amorphous after annealing;
- and
- after annealing the first layer, the second layer, and the third layer, forming a fourth layer on the third layer,
- wherein the fourth layer is operable as an electrode.
A method for forming a capacitor stack, the method comprising:
- forming a first layer on a substrate,
- wherein the first layer is operable as an electrode, and
- wherein the first layer comprises molybdenum oxide;
- forming a second layer on the first layer,
- wherein the second layer comprises a dielectric material,
- wherein the second layer comprises a dopant, and
- wherein the second layer is more than 30% crystalline after a subsequent annealing treatment;
- forming a third layer on the second layer,
- wherein the third layer is operable as a blocking layer,
- wherein the third layer comprises LaAlO3, and;
- after forming the third layer, annealing the first layer, the second layer, and the third layer at a temperature of between about 300 C and 600 C in an oxidizing atmosphere including between about 0% O2 and 20% O2,
- wherein the second layer is crystalline after annealing,
- wherein the third layer is amorphous after annealing;
- and
- after annealing the first layer, the second layer, and the third layer, forming a fourth layer on the third layer,
- wherein the fourth layer is operable as an electrode.
Dependencies are inferred from the claim text.