| 摘要 |
A CMOS image sensor is provided to completely deplete an n-type diffusion region before light comes in when the doping density of an n-type photodiode region is low, by using a transfer transistor including a photodiode with an n-type diffusion region and an electrode pattern of a recessed gate structure. An isolation layer(303) is formed on a semiconductor substrate(300) including an epitaxial layer(301). A nitride layer is formed and patterned to penetrate into the substrate including the epitaxial layer so that a transfer transistor is embodied. A dry etch process is performed on the substrate by using the patterned nitride layer as an etch mask to form a trench for forming a gate of the transfer transistor. A gate oxide layer(311) is formed on the resultant structure. A polycrystalline silicon layer is formed on the gate oxide layer and is patterned to form a recessed gate electrode pattern on the trench.
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