Semiconductor device, semiconductor structure and forming method thereof

A semiconductor device according to an embodiment of the present disclosure includes: a first base fin and a second base fin extending from a substrate; an isolation feature disposed between the first base fin and the second base fin; a first dummy epitaxial layer disposed on the first base fin; a second dummy epitaxial layer disposed on the second base fin; a first insulating layer over the first dummy epitaxial layer; the second insulating layer is positioned above the second pseudo epitaxial layer; a first source/drain feature disposed on the first insulating layer; and a second source/drain feature disposed on the second insulating layer. A thickness of the first dummy epitaxial layer measured from a top surface of the first base fin is less than a thickness of the second dummy epitaxial layer measured from a top surface of the second base fin. The embodiment of the invention also relates to a semiconductor structure and a forming method thereof. 根据本公开实施例的半导体器件包括：第一基底鳍和第二基底鳍，从衬底延伸；隔离部件，设置在第一基底鳍和第二基底鳍之间；第一