Abstract: An embodiment is a semiconductor structure. The semiconductor structure includes a substrate. A fin is on the substrate. The fin includes silicon germanium. An interfacial layer is over the fin. The interfacial layer has a thickness in a range from greater than 0 nm to about 4 nm. A source/drain region is over the interfacial layer. The source/drain region includes silicon germanium.

Abstract: An embodiment is a semiconductor structure. The semiconductor structure includes a substrate. A fin is on the substrate. The fin includes silicon germanium. An interfacial layer is over the fin. The interfacial layer has a thickness in a range from greater than 0 nm to about 4 nm. A source/drain region is over the interfacial layer. The source/drain region includes silicon germanium.

Abstract: An embodiment is a semiconductor structure. The semiconductor structure includes a fin on a substrate. A gate structure is over the fin. A source/drain is in the fin proximate the gate structure. The source/drain includes a bottom layer, a supportive layer over the bottom layer, and a top layer over the supportive layer. The supportive layer has a different property than the bottom layer and the top layer, such as a different material, a different natural lattice constant, a different dopant concentration, and/or a different alloy percent content.

Abstract: A semiconductor device includes a substrate, at least one first isolation structure, at least two second isolation structures, and a plurality of epitaxy structures. The substrate has a plurality of semiconductor fins therein. The first isolation structure is disposed between the semiconductor fins. The semiconductor fins are disposed between the second isolation structures, and the second isolation structures extend into the substrate further than the first isolation structure. The epitaxy structures are respectively disposed on the semiconductor fins. The epitaxy structures are separated from each other, and at least one of the epitaxy structures has a substantially round profile.

Abstract: A semiconductor device includes a substrate, at least one first isolation structure, at least two second isolation structures, and a plurality of epitaxy structures. The substrate has a plurality of semiconductor fins therein. The first isolation structure is disposed between the semiconductor fins. The semiconductor fins are disposed between the second isolation structures, and the second isolation structures extend into the substrate further than the first isolation structure. The epitaxy structures are respectively disposed on the semiconductor fins. The epitaxy structures are separated from each other, and at least one of the epitaxy structures has a substantially round profile.