A semiconductor device including a substrate, a P-MOS single crystal TFT formed on the substrate, and an N-MOS single crystal TFT formed on the P-MOS single crystal TFT. The source region of the P-MOS single crystal TFT and the source region of the N-MOS single crystal TFT may be connected to each other. The P-MOS single crystal TFT and the N-MOS single crystal TFT may share a common gate. Also, the P-MOS single crystal TFT may include a single crystal silicon layer with a crystal plane of (100) and a crystal direction of . The N-MOS single crystal TFT may include a single crystal silicon layer having the same crystal direction as the single crystal silicon layer of the P-MOS single crystal TFT and having a tensile stress greater than the single crystal silicon layer of the P-MOS single crystal TFT.