Abstract: A display device may include a thin film transistor disposed on a substrate, and a display element electrically connected to the thin film transistor. The thin film transistor may include an active pattern including polycrystalline silicon, a gate insulation layer disposed on the active pattern, and a gate electrode disposed on the gate insulation layer. An average value of grain sizes of the active pattern may be in a range of about 400 nm to about 800 nm. An RMS value of a surface roughness of the active pattern may be about 4 nm or less. A method of manufacturing a polycrystalline silicon layer may include cleaning an amorphous silicon layer with hydrofluoric acid, rinsing the amorphous silicon layer with hydrogenated deionized water, and irradiating the amorphous silicon layer with a laser beam having an energy density of about 440 mJ/cm2 to about 490 mJ/cm2.

Abstract: A display device may include a thin film transistor disposed on a substrate, and a display element electrically connected to the thin film transistor. The thin film transistor may include an active pattern including polycrystalline silicon, a gate insulation layer disposed on the active pattern, and a gate electrode disposed on the gate insulation layer. An average value of grain sizes of the active pattern may be in a range of about 400 nm to about 800 nm. An RMS value of a surface roughness of the active pattern may be about 4 nm or less. A method of manufacturing a polycrystalline silicon layer may include cleaning an amorphous silicon layer with hydrofluoric acid, rinsing the amorphous silicon layer with hydrogenated deionized water, and irradiating the amorphous silicon layer with a laser beam having an energy density of about 440 mJ/cm2 to about 490 mJ/cm2.

Abstract: A display device may include a thin film transistor disposed on a substrate, and a display element electrically connected to the thin film transistor. The thin film transistor may include an active pattern including polycrystalline silicon, a gate insulation layer disposed on the active pattern, and a gate electrode disposed on the gate insulation layer. An average value of grain sizes of the active pattern may be in a range of about 400 nm to about 800 nm. An RMS value of a surface roughness of the active pattern may be about 4 nm or less. A method of manufacturing a polycrystalline silicon layer may include cleaning an amorphous silicon layer with hydrofluoric acid, rinsing the amorphous silicon layer with hydrogenated deionized water, and irradiating the amorphous silicon layer with a laser beam having an energy density of about 440 mJ/cm2 to about 490 mJ/cm2.

Abstract: A laser crystallization method includes exciting gas medium in an airtight container to generate laser beams; amplifying the laser beams by reflecting the laser beams between a high reflection mirror and a low reflection mirror respectively disposed facing opposite end portions of the airtight container, wherein a first transparent window and a second transparent window are fixed to respective end portions of the airtight container, and outputting the amplified laser beams; and disposing a cleaning mirror in a path of the laser beams that have propagated through the second transparent window.

Abstract: A display device may include a thin film transistor disposed on a substrate, and a display element electrically connected to the thin film transistor. The thin film transistor may include an active pattern including polycrystalline silicon, a gate insulation layer disposed on the active pattern, and a gate electrode disposed on the gate insulation layer. An average value of grain sizes of the active pattern may be in a range of about 400 nm to about 800 nm. An RMS value of a surface roughness of the active pattern may be about 4 nm or less. A method of manufacturing a polycrystalline silicon layer may include cleaning an amorphous silicon layer with hydrofluoric acid, rinsing the amorphous silicon layer with hydrogenated deionized water, and irradiating the amorphous silicon layer with a laser beam having an energy density of about 440 mJ/cm2 to about 490 mJ/cm2.

Abstract: A laser crystallization method includes exciting gas medium in an airtight container to generate laser beams; amplifying the laser beams by reflecting the laser beams between a high reflection mirror and a low reflection mirror respectively disposed facing opposite end portions of the airtight container, wherein a first transparent window and a second transparent window are fixed to respective end portions of the airtight container, and outputting the amplified laser beams; and disposing a cleaning mirror in a path of the laser beams that have propagated through the second transparent window.