CMOS image sensor and fabricating method thereof

A fabricating method of a CMOS image sensor, comprising the steps of:

• forming a transfer gate on a semiconductor substrate where a device isolation layer is formed;
• forming a first n-type ion implantation region aligned at one side of the transfer gate beneath a region reserved for a spacer of the transfer gate with a first mask, wherein the first n-type ion implantation region has a first width and a first ion implantation depth;
• forming a second n-type ion implantation region aligned at one side of the transfer gate with a second mask to enclose the first n-type ion implantation region, wherein the second n-type ion implantation region has a second width greater than the first width and a second ion implantation depth greater than the first ion implantation depth;
• forming a p-type ion implantation region aligned at one side of the transfer gate with the second mask by implanting p-type ions into upper portions of the first n-type ion implantation region and the second n-type ion implantation region, to thereby reduce a concentration of the p-type ions in the upper portion of the first n-type ion implantation region;
• forming spacers on both sidewalls of the transfer gate;
• and
• forming a floating diffusion region at the other side of the transfer gate.