Patent ID: 11935952
Assignee: SAMSUNG ELECTRONICS CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 16:
17. A method of forming an isolation structure, the method comprising:
removing an upper portion of a substrate to form active fins spaced apart from each other in a second direction on the substrate, each of the active fins extending in a first direction parallel to an upper surface of the substrate, and the second direction being parallel to the upper surface of the substrate and crossing the first direction;
forming a first isolation pattern on the substrate to cover sidewalls of the active fins;
partially removing the active fins and the first isolation pattern and the upper portion of the substrate to form an opening having a bottom lower than a lower surfaces of each of the active fins and a lower surface of the first isolation pattern;
forming a second isolation pattern to fill the opening;
partially removing the active fins, the first isolation pattern, and the second isolation pattern and the upper portion of the substrate to form a first recess having a bottom lower than the lower surfaces of each of the active fins, the lower surface of the first isolation pattern, and a lower surface of the second isolation pattern, the first recess defining an active region on the substrate;
forming a third isolation pattern to fill the first recess; and
removing an upper portions of each of the first isolation pattern, the second isolation pattern, and the third isolation pattern to expose upper portions of the active fins;
forming a dummy gate structure on the active fins, the first isolation pattern, the second isolation pattern and the third isolation patterns to extend in the second direction;
partially removing portions of the active fins at opposite sides in the first direction of the dummy gate structure to form second recesses;
forming source/drain layers on the second recesses, respectively; and
replacing the dummy gate structure with a gate structure,
wherein the active region includes a first sidewall and a second sidewalls opposite to each other in the second direction, and
wherein the first sidewall of the active region includes a lower portion contacting the third isolation pattern and an upper portion contacting the second isolation pattern, and has a staircase shape.