Semiconductor device including strained germanium and method for manufacturing the same

A method for manufacturing a semiconductor device, the method comprising:

• forming a sacrificial layer on a first substrate, the sacrificial layer being made of a material whose lattice constant is different from a lattice constant of germanium (Ge) by about 0.2% to about 5% in absolute value;
• forming a germanium (Ge) layer on the sacrificial layer such that the sacrificial layer is disposed between the first substrate and the germanium (Ge) layer and a strain as a result of the difference in lattice constant between the germanium (Ge) layer and the sacrificial layer is applied to the germanium (Ge) layer;
• forming an insulation layer on a second substrate;
• bonding the germanium (Ge) layer formed on the sacrificial layer onto the insulation layer;
• and
• selectively etching the sacrificial layer to concurrently remove the sacrificial layer and the first substrate from the germanium (Ge) layer,
• wherein the strain is maintained in the germanium (Ge) layer after the removing of the sacrificial layer.