Influence of oxygen on copper gettering in hydrocarbon molecular ion implanted region using atom probe tomography

Abstract The gettering behavior in a hydrocarbon molecular (C3H5) ion implanted region was investigated using atom probe tomography (APT) with the aim of improving electrical properties of CMOS image sensors (CISs) and stacked CISs. APT clarified the formation of carbon atom agglomerates with copper and oxygen gettering capability in the C3H5 ion implanted region. However, there were no oxygen atoms near the copper atoms in the C3H5 ion implanted region. In addition, the copper gettering capability of each carbon atom agglomerates decreased with increasing ratio of the number of oxygen atoms to that of carbon atoms in the carbon atom agglomerates. The copper and oxygen gettering mechanism was considered to involve the formation of a complex with carbon-containing gettering sites. Oxygen degrades the copper gettering capability of carbon atom agglomerates by the formation of stable complexes with carbon-containing gettering sites, which can also act as copper gettering sites. Consequently, the oxygen concentration in the C3H5 ion implanted regions is an important factor in improving the electrical properties of CISs and stacked CISs.