Monolayer segregation of As atoms at the interface between gate oxide and Si substrate in a metal-oxide-semiconductor field effect transistor by three-dimensional atom-probe technique

Atom-probe technique was applied to analyze three-dimensional dopant distribution in Si substrate of metal-oxide-semiconductor field effect transistor (MOSFET) structure. As a result, three-dimensional As atom distribution implanted in Si was obtained. The quantification of the As atom distribution in a depth direction was confirmed as compared with the one-dimensional distribution measured by secondary ion mass spectroscopy. Moreover, monolayer segregation of As atoms at the interface between gate oxide and Si substrate was clearly observed. This result shows the possibility to clarify discrete dopant distribution in Si substrate related to the characteristic variation of MOSFETs.