CMOS IMAGE SENSOR WITH IMPROVED CHARGE TRANSFER EFFICIENCY AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A CMOS image sensor and a method for manufacturing the same are provided to improve charge transfer efficiency by forming a heavily doped region in a photodiode spaced apart from a gate electrode of a transfer transistor. CONSTITUTION: A p-type epitaxial layer(22) is formed on a p-type substrate(21). A gate electrode(29b) of a transfer transistor is formed on the epitaxial layer, and a spacer(29c) is formed at both sidewalls of the gate electrode. A deep n-type diffusion layer(24) of a photodiode is formed in the epitaxial layer, and a shallow p-type diffusion layer(25) is formed between the n-type diffusion layer and the epitaxial layer. A p+ doping region(27) is formed in the p-type diffusion region in order to ground the photodiode. Since the potential profile has a slope(S), the charge transfer efficiency is increased.