Static random access memory and method for fabricating the same
AssigneeUnited Microelectronics Corp.
InventorsChing-Wen Hung, Chun-Hsien Lin, Chien-Hung Chen
Life of this patent
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Abstract
A method for fabricating a static random access memory (SRAM) includes the steps of: forming a gate structure on a substrate; forming an epitaxial layer adjacent to the gate structure; forming a first interlayer dielectric (ILD) layer around the gate structure; transforming the gate structure into a metal gate; forming a contact hole exposing the epitaxial layer, forming a barrier layer in the contact hole, forming a metal layer on the barrier layer, and then planarizing the metal layer and the barrier layer to form a contact plug. Preferably, a bottom portion of the barrier layer includes a titanium rich portion and a top portion of the barrier layer includes a nitrogen rich portion.
Claims7
A static random access memory (SRAM), comprising:
- a first gate structure on a substrate, wherein the first gate structure comprises:
- an interfacial layer on the substrate;
- a high-k dielectric layer on the interfacial layer;
- and
- a work function metal layer on the high-k dielectric layer;
- an epitaxial layer adjacent to the first gate structure;
- a first contact plug on the epitaxial layer;
- a second contact plug on the first gate structure, wherein a sidewall of the second contact plug is aligned with a sidewall of the high-k dielectric layer;
- a second gate structure adjacent to the first contact plug, wherein the first contact plug is between the first gate structure and the second gate structure;
- a first interlayer dielectric (ILD) layer around the first contact plug, the second contact plug, the first gate structure, and the second gate structure;
- a third contact plug on the first contact plug and the second gate structure, wherein a bottom surface of the third contact plug contacting the second gate structure is lower than a top surface of the first ILD layer;
- a fourth contact plug on the second contact plug, wherein a top surface of the second contact plug is less than a bottom surface of the fourth contact plug;
- and
- a second ILD layer around the third contact plug and the fourth contact plug.
Dependencies are inferred from the claim text.