Method of forming a metal to polysilicon contact in oxygen environment
AssigneeMicron Technology, Inc.
InventorWerner Juengling
Life of this patent
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Abstract
A method for forming a contact capable of tolerating an O2 environment up to several hundred degrees Celsius for several hours is disclosed. To slow down the metal oxide front of the metal layer at the metal-polysilicon interface, the metal layer is surrounded by one or more oxygen sink spacers and layers. These oxygen sink spacers and layers are oxidized before the metal layer at the bottom of the plug is oxidized. Accordingly, the conductive connection between the polysilicon and any device built on top of the barrier layer is preserved.
Claims58
A metal-polysilicon contact providing electrical connection on a substrate, said metal-polysilicon contact comprising:
- a polysilicon layer;
- a barrier layer formed over said polysilicon layer;
- at least one conductive layer formed over said barrier layer, said conductive layer having a thickness of about 100 to 300 Angstroms, said conductive layer being formed in an opening of an insulating layer and having at least one vertically extending surface in said opening;
- and
- at least one oxygen sink layer formed adjacent to said conductive layer and in between said insulating layer and said conductive layer, said oxygen sink layer being capable of absorbing oxygen.
A memory cell, comprising:
- a substrate;
- a transistor including a gate fabricated on said substrate and including a source/drain region in said substrate disposed adjacent to said gate;
- a capacitor including a first electrode, a dielectric layer and a second electrode, said first electrode having a surface aligned over said source/drain region;
- and
- a metal-polysilicon structure providing electrical contact between said source/drain region and said surface of said first electrode, said metal-polysilicon structure comprising a polysilicon layer formed over said substrate, a barrier layer formed over said polysilicon layer, at least one conductive layer formed over said barrier layer, and at least one oxygen sink layer formed adjacent to said conductive layer, said oxygen sink layer being capable of absorbing oxygen.
A metal-polysilicon contact providing electrical connection on a substrate, said metal-polysilicon contact comprising:
- a polysilicon layer;
- a barrier layer formed over said polysilicon layer;
- at least one conductive layer formed over said barrier layer;
- a plurality of spaced oxygen sink layers formed adjacent to said conductive layer, said plurality of spaced oxygen sink layers being capable of absorbing oxygen;
- and
- a capacitor formed over and in contact with said conductive layer.
Dependencies are inferred from the claim text.