Abstract: A method of fabricating a stripe photodiode element, for an image sensor cell, has been developed. The stripe photodiode element is comprised of a narrow width, serpentine shaped, lightly doped N type region, in a P well region. The use of the serpentine shaped region results in increased photon collection area, when compared to counterparts fabricated using non-serpentine shaped patterns. In addition the use of the serpentine shaped N type regions allow both vertical, as well as horizontal depletion regions, to result, thus increasing the quantum efficiency of the photodiode element. The combination of narrow width, and a reduced dopant level, for the N type serpentine shaped region, result in a fully depleted photodiode element.

Abstract: A method for forming a high performance photodiode with tightly-controlled junction profile for CMOS image sensor with STI process. The following steps are performed: providing a substrate; forming a hard mask layer for defining a pattern on the substrate; etching the substrate on the surface of the substrate not covered by the hard mask layer to form a shallow trench; growing an oxide lining in the shallow trench by a thermal oxidation process; performing a first thermal annealing; defining an n-well region in the shallow trench; implanting the n-well region; performing a second thermal annealing; forming a silicon oxide layer on the substrate to fill in the shallow trench; removing a portion of the silicon oxide layer on the substrate such that the portion in the shallow trench remains; removing the hard mask layer; and forming a transistor on the substrate, wherein the transistor comprises a gate structure, a source region, and a drain region.

Abstract: A process for fabricating a lateral photodiode element, for an image sensor cell, with an increased depletion region, has been developed. The process features protecting a portion of the semiconductor substrate from ion implantation procedures used to create the P well, and the N well components of the lateral photodiode element. The protected region, or the space between the P well and N well regions, allows a larger depletion region to be realized, when compared to lateral photodiode elements in which the N well and P well regions butt. The space between the P well and N well regions, between about 0.2 to 0.4 um, result in the desired P well—intrinsic or P type semiconductor substrate—N well, (P-I-N), lateral photodiode element.

Abstract: A method of fabricating a stripe photodiode element, for an image sensor cell, has been developed. The stripe photodiode element is comprised of a narrow width, serpentine shaped, lightly doped N type region, in a P well region. The use of the serpentine shaped region results in increased photon collection area, when compared to counterparts fabricated using non-serpentine shaped patterns. In addition the use of the serpentine shaped N type regions allow both vertical, as well as horizontal depletion regions, to result, thus increasing the quantum efficiency of the photodiode element. The combination of narrow width, and a reduced dopant level, for the N type serpentine shaped region, result in a fully depleted photodiode element.