Display device and method of manufacturing thin film transistor

A display device, comprising:

• a first substrate having a first thin film transistor and a second thin film transistor, wherein the first thin film transistor and the second thin film transistor each comprises:
• a light shielding layer disposed on the first substrate;
• a buffer layer covered above and on a lateral side of the light shielding layer;
• a semiconductor layer disposed above the buffer layer, such that the buffer layer is located between the semiconductor layer and the light shielding layer, and the semiconductor layer having a first doped region, a second doped region and a channel region between the first doped region and the second doped region;
• a first insulating layer disposed above the semiconductor layer;
• a first metal layer disposed above the first insulating layer, and having an overlapped region with the channel region in a vertical projection direction;
• a second insulating layer covered on the first metal layer;
• and
• a second metal layer disposed above the second insulating layer, and connected to the first doped region or the second doped region;
• wherein a projection area of the semiconductor layer projected vertically on the first substrate is less than a projection area of the light shielding layer projected vertically on the first substrate.