Re-crystallization Behavior of Amorphous Layer in Hydrocarbon Molecular Ion Implanted Region Using Flash Lamp Annealing

摘要

We have developed hydrocarbon molecular ion implanted epitaxial wafers for advanced CMOS image sensors. The hydrocarbon molecular ion implanted region has the highest gettering capability for metallic impurities and plays a barrier role for-diffused oxygen atoms from CZ grown Si substrate. In addition, implanted hydrogen atoms diffuse out and passivate process-induced defects in device process. It is previously reported that high-dose hydrocarbon molecular ion implantation enhances these characteristics even more. However in high-dose implantation condition, stacking faults are formed in epitaxial layer. In this study, the flash lamp annealing is investigated as recovery annealing after high-dose implantation. The flash lamp annealing is expected to change the re-crystallization behavior of amorphous layer and suppress the formation of stacking faults in epitaxial layer without diffusion of hydrogen atoms from implanted region. Consequently, by the flash lamp annealing after high-dose implantation the stacking faults in epitaxial layer are perfectly suppressed. Furthermore, high concentration hydrogen remains in implanted region after FLA and epitaxial growth process due to change of defect morphology. Without recovery annealing after high-dose implantation, amorphous layer is re-crystallized in ramp-up time of epitaxial growth process and clamshell type defects are formed. Conversely, by flash lamp annealing high density small defect are formed. These high density small defects are contributed to remain hydrogen atoms in implanted region.