The polysilicon pattern 138 may include a main body MP positioned on the buffer layer 120 and a first protrusion PP1 and a second protrusion PP2 each protruding upward from an upper surface of the main body MP. The main body MP may have the second thickness TH2, and each of the first protrusion PP1 and the second protrusion PP2 may have the third thickness TH3. In this case, the first region R1 may include the first protrusion PP1, and the second region R2 may include the second protrusion PP2.

In an embodiment, the first thickness TH1, which is a thickness of each of the first region R1 and the second region R2 of the polysilicon pattern 138, may be greater than about 250 ? and less than about 470 ?. Further, the second thickness TH2, which is a thickness of the third region R3 of the polysilicon pattern 138, may be about 250 ? to about 450 ?.

Accordingly, a thickness of the main body MP of the polysilicon pattern 138 may be about 250 ? to about 450 ?, and the third thickness TH3, which is a thickness of each of the first protrusion PP1 and the second protrusion PP2 of the polysilicon pattern 138, may be greater than 0 ? and less than about 220 ?. In an embodiment, the thickness of each of the first protrusion PP1 and the second protrusion PP2 may be about 5% to about 15% of the thickness of the main body MP. In other words, the third thickness TH3 may be about 5% to about 15% of the second thickness TH2.