A semiconductor device structure, along with methods of forming such, are described. The structure includes a first fin, a second fin adjacent the first fin, and a third fin adjacent the second fin. The structure further includes a first source/drain epitaxial feature merged with a second source/drain epitaxial feature. The structure further includes a third source/drain epitaxial feature, and a first liner positioned at a first distance away from a first plane defined by a first sidewall of the first fin and a second distance away from a second plane defined by a second sidewall of the second fin. The first distance is substantially the same as the second distance, and the merged first and second source/drain epitaxial features is disposed over the first liner. The structure further includes a dielectric feature disposed between the second source/drain epitaxial feature and the third source/drain epitaxial feature.