Asymmetric MIM capacitor for DRAM devices
AssigneeIntermolecular, Inc.
InventorsHanhong Chen, Hiroyuki Ode
Life of this patent
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Abstract
A bilayer second electrode for a MIM DRAM capacitor is formed wherein the layer of the electrode that is in contact with the dielectric layer (i.e. bottom layer) has a composition that is resistant to oxidation during subsequent anneal steps and have rutile templating capability. Examples include SnO2 and RuO2. The capacitor stack including the bottom layer is subjected to a PMA treatment to reduce the oxygen vacancies in the dielectric layer and reduce the interface states at the dielectric/second electrode interface. The other component of the bilayer (i.e. top layer) is a high work function, high conductivity metal or conductive metal compound.
Claims20
A semiconductor layer stack comprising:
- a first electrode layer;
- a dielectric layer on the first electrode layer,
- wherein the dielectric layer has a rutile crystal structure;
- and
- a bilayer second electrode structure on the dielectric layer,
- wherein the bilayer second electrode structure comprises a bottom layer on the dielectric layer and a top layer on the bottom layer, and
- wherein the bottom layer has a tetragonal crystal structure,
- the tetragonal crystal structure being compatible with the rutile crystal structure of the dielectric layer such that a low k interfacial layer is not formed at an interface formed by the bottom layer and the dielectric layer.
A semiconductor layer stack comprising:
- a dielectric layer,
- wherein the dielectric layer has a rutile crystal structure;
- and
- a bottom layer formed on the dielectric layer,
- wherein the bottom layer comprises a conductive metal oxide;
- and
- a top layer formed on the bottom layer;
- wherein the bottom layer has a tetragonal crystal structure,
- the tetragonal crystal structure being compatible with the rutile crystal structure of the dielectric layer such that a low k interfacial layer is not formed at an interface formed by the bottom layer and the dielectric layer.
Dependencies are inferred from the claim text.