Patent ID: 8610234

Claim:
A photo detector configured to absorb light in a unit pixel of an image sensor transforming the absorbed light to an electrical signal, comprising: a substrate in which a V-shaped groove having a predetermined angle is formed; a light-absorbing part formed in a floated structure above the V-shaped groove, light being incident to the light-absorbing part; an oxide film formed in between the light-absorbing part and the V-shaped groove, tunneling occurring in the oxide film; a source formed adjacent to the oxide film on a slope of one side of the V-shaped groove and separated from the light-absorbing part by the oxide film; a drain formed adjacent to the oxide film on a slope of the other side of the V-shaped groove and separated from the light-absorbing part by the oxide film; and a channel interposed between the source and the drain along the V-shaped groove and configured to form flow of an electric current between the source and the drain, wherein the light-absorbing part is doped with first type impurities, and the source and the drain are doped with second type impurities, wherein the light-absorbing part is insulated from the source and the drain by the oxide film, wherein electron-hole pairs are generated in the light-absorbing part by the light incident to the light-absorbing part, tunneling occurs in between at least one of the source and drain and the light-absorbing part by an electric field concentrated in the oxide film, electrons of the electron-hole pairs are moved to at least one of the source and the drain from the light-absorbing part by the tunneling, 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.