An image device includes a first active region and a second active region disposed on a substrate. Each of the first active region and the second active region includes a gate insulating layer disposed on the substrate and a gate electrode disposed on the gate insulating layer. At least one of the first active region and the second active region further includes a first passivation layer containing fluorine (F) disposed between the gate insulating layer and the gate electrode. A concentration of fluorine in the gate insulating layer is higher than a concentration of fluorine in the gate electrode.