Patent ID: 8669598

Claim:
A unit pixel of an image sensor configured to transform absorbed light to an electrical signal, comprising: a photo detector configured to cause an electric current to flow using a change in the quantity of electric charge caused by incident light; a select device configured to output the electric current generated by the photo detector to a unit pixel output terminal, wherein the photo detector comprises: a light-absorbing part formed in a floated structure and configured to absorbed light; an oxide film being in contact with one surface of the light-absorbing part; a source being in contact with one side of the other surface of the oxide film and separated from the light-absorbing part with the oxide film therebetween; a drain facing the source so as to be in contact with the other side of the other surface of the oxide film and separated from the light-absorbing part with the oxide film therebetween; and a channel formed between the source and the drain and configured to form flow of an electric current between the source and drain, wherein the select device comprises: a drain being connected with the source of the photo detector; a source being accessed to the unit pixel output terminal; and a gate configured to receive a control signal from an outside source, and a switching operation is performed based on the control signal, wherein the light-absorbing part is doped with first type impurities, and the source and the drain and the photo detector are doped with second type impurities, wherein the light-absorbing part is insulated from the source and the drain of the light-absorbing part by the oxide film, and wherein electrons of electron-hole pairs generated by the absorbed light are moved to the source and the drain by a tunneling phenomenon occurred by an electric field concentrated in the oxide film, and the flow of the electric current of the channel is controlled by a change in the quantity of electric charge of the light-absorbing part caused by the moving of the electrons.