Solid-state image sensor and method for fabricating the same

摘要

A solid-state image sensor comprises a semiconductor substrate of a first conductivity type having a color pixel region (10a) and a black pixel region (10b) ; a first well of the first conductivity type formed in the color pixel region (10a); a second well of the first conductivity type formed in the black pixel region (10b) ; a third well of a second conductivity type formed, surrounding the second well and isolating the second well from the rest region of the semiconductor substrate; a color pixel formed in the first well in the color pixel region (10a) and including a first photodiode and a first read transistor for reading a signal generated by the first photodiode; and a black pixel formed in the second well in the black pixel region and including a second photodiode and a second read transistor for reading a signal generated by the second photodiode. The first well includes a first buried impurity doped layer of the first conductivity type formed in a bottom thereof in a region where the first read transistor is formed. The second well includes a second buried impurity doped layer of the first conductivity type formed in a bottom thereof in a region where the second photodiode is formed and a region where the second read transistor is formed.