A layout of a semiconductor device and a method of forming a semiconductor device, the semiconductor device include a first fin and a second fin disposed on a substrate, a gate and a spacer. The first fin and the second fin both include two opposite edges, and the gate completely covers the two opposite edges of the first fin and only covers one sidewall of the two opposite edges of the second fin. The spacer is disposed at two sides of the gate, and the spacer covers another sidewall of the two opposite edges of the second fin.