A method for fabricating a semiconductor device includes providing a first wafer comprising a substrate and a first semiconductor material layer, bonding the first wafer to a second wafer, the second wafer comprising a sacrificial layer and a second semiconductor material layer, removing the sacrificial layer, patterning the bonded wafers to create a first structure and a second structure, removing the second semiconductor material from the first structure, forming a first type of transistor in the first semiconductor material of the first structure, and forming a second type of transistor in the second semiconductor material of the second structure.