In an embodiment, a method includes forming a first fin and a second fin within an insulation material over a substrate, the first fin and the second fin includes different materials, the insulation material being interposed between the first fin and the second fin, the first fin having a first width and the second fin having a second width; forming a first capping layer over the first fin; and forming a second capping layer over the second fin, the first capping layer having a first thickness, the second capping layer having a second thickness different from the first thickness.