Display device

A display device comprising:

• a substrate;
• a first insulating layer disposed on the substrate and comprising silicon nitride;
• a second insulating layer disposed on the first insulating layer and comprising silicon oxide;
• and
• a semiconductor layer disposed on the second insulating layer and comprising polycrystalline silicon,
• wherein a film density of the second insulating layer is in a range of about 2.2 g/cm3 to about 2.25 g/cm3.

A display device comprising:

• a substrate;
• a first insulating layer disposed on the substrate and comprising silicon nitride;
• a second insulating layer disposed on the first insulating layer and comprising silicon oxide;
• and
• a semiconductor layer disposed on the second insulating layer and comprising polycrystalline silicon,
• wherein the first insulating layer comprises a first surface facing the substrate and a second surface opposite to the first surface,
• a concentration of fluorine contained in the first insulating layer has a first peak value on at least one of the first surface and the second surface of the first insulating layer, and
• the first peak value of the concentration of the fluorine is about 2.5 times or less a concentration of fluorine at a center point of the first insulating layer in a thickness direction.