Influence of carbon on Ni gettering in C2Hx+ and SiHy+ mixture molecular-ion-implanted silicon epitaxial wafer

For the mass production of highly sensitive CMOS image sensors, the development of a high-performance gettering technique, which can remove metallic impurity contaminations from device active region with a low-concentration impurity such as carbon or oxygen is required. To address this issue, we developed a hydrocarbon (C2Hx+) and silicon-hydride (SiHy+) mixture molecular ion implantation technique to form a gettering sink even under low carbon doses. However, the influence of carbon on gettering behavior in the molecular-ion-implanted region has never been investigated. In this study, we investigated the influence of the C2Hx+ ratio on the gettering behavior in the molecular-ion-implantation region by changing the cooling method in Ni contamination diffusion heat treatment between quenching and slow cooling. As a result, we clarified that the gettering behavior is dependent on the defect type that changes depending on the C2Hx+ ratio. These results suggest that mixture molecular ion implantation is effective in designing the gettering sinks via the changes in C2Hx+ ratio.