Asymmetric gate cut isolation for SRAM
Methods of forming a gate cut isolation for an SRAM include forming a first and second active nanostructures adjacent to each other and separated by a space; forming a sacrificial liner over at least a side of the first active nanostructure facing the space, causing a first distance between a remaining portion of the space and the first active nanostructure to be greater than a second distance between the remaining portion of the space and the second active nanostructure. A gate cut isolation is formed in the remaining portion of the space such that it is closer to the second active nanostructure than the first active nanostructure. The sacrificial liner is removed, and gates formed over the active nanostructures with the gates separated from each other by the gate cut isolation. An SRAM including the gate cut isolation and an IC structure including the SRAM are also included.
1. An integrated circuit (IC), comprising:
a static random access memory (SRAM) including:
a first n-type field effect transistor (NFET) having a first active nanostructure on a substrate, and a first gate surrounding the first active nanostructure;
a first p-type field effect transistor (PFET) having a second active nanostructure on the substrate adjacent to the first active nanostructure of the first NFET, and a second gate surrounding the second active nanostructure; and
a first gate cut isolation separating the first gate from the second gate, the first gate cut isolation being closer to the second active nanostructure of the first PFET than the first active nanostructure of the first NFET;
a logic region including:
a second NFET having a third active nanostructure on the substrate, and a third gate surrounding the third active nanostructure;
a second PFET having a fourth active nanostructure on the substrate adjacent to the third active nanostructure of the second NFET, and a fourth gate surrounding the fourth active nanostructure; and
a second gate cut isolation equidistant between the third and fourth active nanostructures.
2. The IC of claim 1 , wherein the gate cut isolation includes a lower portion and a unitary, wider, upper portion, the unitary, wider upper portion extending above an upper surface of the second active nanostructure of the first PFET.
3. The IC of claim 1 , wherein the first and second active nanostructures include semiconductor nanosheets separated by gate material, and further comprising a protective layer positioned between the gate cut isolation and a side of the second active nanostructure of the first PFET.
4. The IC of claim 1 , wherein the first and second active nanostructures each include a semiconductor fin.
5. The IC of claim 1 , wherein the first and second active nanostructures each include a semiconductor nanosheet stack.
6. The IC of claim 1 , further comprising a conductive strap positioned over the second gate cut isolation to electrically couple the third and fourth gates.
7. An static random access memory (SRAM), comprising:
an n-type field effect transistor (NFET) having a first active nanostructure on a substrate, and a first gate surrounding the first active nanostructure;
a p-type field effect transistor (PFET) having a second active nanostructure on the substrate adjacent to the first active nanostructure of the NFET, and a second gate surrounding the second active nanostructure; and
a gate cut isolation separating the first gate from the second gate, the gate cut isolation being closer to the second active nanostructure of the PFET than the first active nanostructure of the NFET;
a logic region including:
a second NFET having a third active nanostructure on the substrate, and a third gate surrounding the third active nanostructure;
a second PFET having a fourth active nanostructure on the substrate adjacent to the third active nanostructure of the second NFET, and a fourth gate surrounding the fourth active nanostructure; and
a second gate cut isolation equidistant between the third and fourth active nanostructures.
8. The SRAM of claim 7 , wherein the gate cut isolation includes a lower portion, and a unitary, wider, upper portion, the unitary, wider, upper portion extending above an upper surface of the second active nanostructure of the PFET.
9. The SRAM of claim 8 , wherein the first and second active nanostructures include semiconductor nanosheets separated by gate material, and further comprising a protective layer positioned between the lower portion of the gate cut isolation and a side of the second active nanostructure of the PFET.
10. The SRAM of claim 7 , wherein the first and second active nanostructures include semiconductor nanosheets separated by gate material, and further comprising a protective layer positioned between the gate cut isolation and a side of the second active nanostructure of the PFET.