mask formation and the etching process can be omitted after depositing the oxide layer 45 and the process using the planar pl mask can be performed after depositing the amorphous silicon layer 49 as shown in fig3 d a gate electrode i e a transfer gate tx including a conductive layer 52 and a plurality of spacers 53 is formed afterwards an ion implantation process is performed onto the amorphous silicon layer 49 thereby forming a photodiode pd comprised of a p 0 type region 50 and an n type region 51 fig4 a to 4 c are cross sectional views illustrating a method for fabricating a cmos image sensor in accordance with a second embodiment of the present invention meanwhile the same reference numerals are used with respect to the same constitution elements identical with those of the first embodiment of the present invention and detailed explanations about the identical constitution elements are omitted as shown in fig4 a a trench 44 for forming a field oxide layer with a sti structure is formed in a p type semiconductor layer comprised of a p type epitaxial layer not shown and a highly doped p type substrate 40 for instance a pad oxide layer not shown and a pad nitride layer not shown are deposited and then the pad oxide layer not shown and the pad nitride layer not shown are etched by using a photoresist pattern not shown as an etch mask thereby defining a trench formation region thereafter the photoresist pattern.