Image display device using transistors each having a polycrystalline semiconductor layer

An image display device using transistors each having a polycrystalline semiconductor layer, comprising:

• a gate electrode formed on an upper surface of the polycrystalline semiconductor layer with an insulating film interposed therebetween, a drain region being formed in the polycrystalline semiconductor layer on one side of the gate electrode, and a source region being formed in the polycrystalline semiconductor layer on another side of the gate electrode;
• an activated P-type impurity added to the polycrystalline semiconductor layer in an area underlying the gate electrode;
• and
• an activated N-type impurity added to the polycrystalline semiconductor layer in an area excluding the area underlying the gate electrode, wherein the polycrystalline semiconductor layer has areas which respectively extend from the area underlying the gate electrode to the drain region and the source region and in which the activated P-type impurity is distributed to gradually decrease from the area underlying the gate electrode toward the drain region and the source region, respectively.