Three-dimensional (3D) Atom Probe Tomography (APT) had been used to study carbon segregation at gate oxide/Si substrate interface of MOSFET-based devices with single-atom sensitivity and sub-nanometer spatial resolution. [1] Figure 1213 shows cross-sectional TEM images and 3D APT maps of a good MOSFET structure and a failing MOSFET structure with a shifted threshold voltage, respectively. The 3D atomic images of a full section of the samples were obtained by ions collected from each sample. A small amount of carbon, piled up at the interface between the gate oxide (G_ox) and Si substrate in the failing structure, was obviously detected by APT technique. However, such carbon content cannot be detected by using TEM-EDS technique due to its poor sensitivity or ToF-SIMS technique due to its poor spatial resolution.

[1] Ju-heon Kim, Euna Ok, Hyunmi Sim, Dongkeun Na, Ho Seok Song, Dae Hyun Kim, Yong-beom Cho, Seok-jun Won, Tae-Soo Park, Samsung Electronics Co., Ltd, Impact of carbon on threshold voltage shift in MOSFET studied by 3D atom probe tomography, Proceedings from the 43rd International Symposium for Testing and Failure Analysis, ISTFA 2017.