US Patent 10157748 Fin profile improvement for high performance transistor

A finFET semiconductor device and method for fabricating such a device are presented. The semiconductor device includes a first fin formed in a first semiconducting layer, a second fin formed in a second semiconductor layer, and an insulating layer disposed between the first fin and the second fin. The first fin, the second fin, and the insulating layer form a stacked structure above a substrate. Sidewalls of the first fin are substantially more vertical than sidewalls of the second fin.