Characterization of arsenic segregation at Si/SiO2 interface by 3D atom probe tomography

Dopant loss due to the segregation and dopant pile up at the Si/SiO2 interface are crucial phenomena in the scaling trend of MOSFET devices for the 22-nm technology node. Arsenic segregation and pile-up at the Si/SiO2 interface have been studied by the atom probe tomography (APT) technique which allows the 3D observation and the chemical analyses of dopant distribution with the atomic scale resolution. Arsenic (10-16 at/cm², 32 keV) was implanted in mono-crystalline silicon and then annealed at 900 °C for 6 h after a cleaning step and an oxide growing. The thickness of the segregation layer was determined at 2.3 nm containing 9.36×10-14 at/cm² dose of segregated arsenic. Finally, the obtained arsenic segregated dose has been compared to the resistivity profile performed by spreading resist ance profiling technique.