A method includes the following operations: (i) receiving a FET precursor including a first fin and a second fin, each of the first fin and the second fin having nanowire channels and sacrificial layers; (ii) forming a dummy gate traversing the first and second fins, thereby defining channel regions of the first and second fins under the dummy gate; (iii) forming source/drain features from exposed portions of the first and second fins; (iv) removing the dummy gate to expose the channel regions of the first and second fins; and (v) suspending the nanowire channels of the first and second fins by removing portions of the sacrificial layers of the first and second fins.