| 摘要 |
An image sensor and a method for fabricating the same are disclosed, in which an impurity implantation layer having a predetermined thickness is formed on a source diffusion layer, thereby controlling a substantial contact point between a contact plug and the source diffusion layer upward from a surface of a semiconductor substrate. As a result, it is possible to minimize a length of an open hole, which is a main channel of the contact plug, so that the open hole has the sufficiently large size, thereby inducing the improvement of the contact quality between the contact plug and the source diffusion layer. Also, in case of the CMOS image sensor, in state the impurity implantation layer having the impurity selectively implanted is formed on the source diffusion layer, the impurity implantation layer is electrically connected with the source diffusion layer. Accordingly, without the additional process such as highly-impurity implantation and formation of salicide layer, it is possible for the source diffusion layer to increase the impurity concentration of impurity therein. Eventually, in case of realizing the image sensor according to the present invention, it is possible to the greatest contact quality between the contact plug and the source diffusion layer. In case of realizing the greatest contact quality between the contact plug and the source diffusion layer with the additional formation of the impurity implantation layer, for example, the source diffusion layer normally performs the function of converting the optical charges generated by the photodiode to voltage constituents. Thus, the completed image sensor according to the present invention realizes the great image quality.
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