A display device is provided, which includes a substrate structure containing a substrate with a pixel region, and the pixel region includes an aperture region. A metal oxide semiconductor transistor is disposed over the substrate and includes a metal oxide semiconductor layer with a first channel region, a first gate electrode corresponding to the first channel region, and a silicon oxide insulating layer on the metal oxide semiconductor layer. The silicon oxide insulating layer includes an opening corresponding to the aperture region. A polysilicon transistor is disposed over the substrate. The display device also includes an opposite substrate structure, and a display medium between the substrate structure and the opposite substrate structure.