US Patent 10418493 Tight pitch stack nanowire isolation

Devices and methods for forming a tight pitch stack nanowire without shallow trench isolation including a base nanosheet formed on a substrate. At least one fin are formed, and at least one dummy gate is formed over the at least two fins, on the base nanosheet, the at least two fins including at least two alternating layers of a first material and a second material. The base nanosheet is replaced with a blanket dielectric to form a shallow trench isolation (STI) around the at least one fin and around the at least one dummy gate. A gate replacement is performed to replace the at least one dummy gate and the second material with a gate conductor material and a gate cap to form gate structures.