Gettering mechanism in hydrocarbon-molecular-ion-implanted epitaxial silicon wafers revealed by three-dimensional atom imaging

Abstract

The interaction of iron (Fe) with defects induced by a high hydrocarbon-molecular-ion-implantation dose of 1 × 1016 cm−2 in a Czochralski-grown silicon substrate and an epitaxial growth layer was investigated using secondary ion mass spectroscopy, transmission electron microscopy, and laser-assisted atom probe tomography (L-APT). High-dose hydrocarbon-molecular-ion-implantation formed two types of defects in the projection range: stacking faults and carbon agglomerates. It was demonstrated that the dominant gettering mechanisms of the two types of defects differ. Carbon agglomerates formed by implantation of the epitaxial growth layer exhibited high gettering efficiency for Fe. The L-APT data indicated that the Fe gettering efficiency is strongly affected by the distribution of oxygen atoms in carbon agglomerates. It is suggested that Fe gettering on agglomerates is due to the strong electronic interaction between carbon agglomerates and Fe but suppressed by oxygen atoms in agglomerates.

Proximity Gettering Design of Hydrocarbon–Molecular–Ion–Implanted Silicon Wafers Using Dark Current Spectroscopy for CMOS Image Sensors

“…Our proposal gettering design concept for silicon wafer production leaves intact gettering sinks in the epitaxial layer after backside grinding and the CMP process in BSI fabrication. We previously reported that the metallic impurity gettering capability of this wafer was higher than that in the CZ silicon substrate using APT [60,61]. Because the gettering capability depends on the depth profile of gettering sinks in the silicon epitaxial layer.…”

“…CMOS image sensor manufacturers require for a way of dealing with these issues. We propose using hydrocarbon–molecular–ion–implanted epitaxial silicon wafer [60,61].…”

Reduction of Dark Current in CMOS Image Sensor Pixels Using Hydrocarbon-Molecular-Ion-Implanted Double Epitaxial Si Wafers

“…In a previous study, we demonstrated that these 5 nm defects induced by a high C 3 H 6 -ion implantation dose of 1 × 10 16 cm −2 in the CZ-Si substrate and the first epitaxial layer also consisted of C and I agglomerates [ 38 ]. L-APT data in high-dose C 3 H 6 -ion-implanted samples indicated a difference in the O distribution between the 5 nm defects induced in the CZ-Si substrate and the first epitaxial layer [ 38 , 39 ]. This implies a significant difference in the morphology of 5 nm defects between the CZ-Si substrate and the first epitaxial layer.…”

“…In the previous study, we found that defects formed upon C 3 H 6 -ion-implantation at a high dose of 1 × 10 16 cm −2 in the first epitaxial layer are C– I agglomerates without O atoms [ 38 , 39 ]. This tendency of the O distribution in defects in the previous study is in good agreement with that of defects in the double epitaxial Si wafer formed after the device process in the current study.…”

“…In the previous study, we found that defects formed upon C3H6-ion-implantation at a high dose of 1 × 10 16 cm −2 in the first epitaxial layer are C-I agglomerates without O atoms [38,39]. This tendency of the O distribution in defects in the previous study is in good agreement with that of defects in the The proximity histograms (proxigrams) were calculated by IVAS to reveal the evolution of the C and O concentrations from the isoconcentration surfaces of C. Figure 12c,d shows proxigrams for C and O of C 3 H 6 -ion-implanted single and double epitaxial Si wafers, respectively.…”