Profiling N-Type Dopants in Silicon

Abstract

Variously doped n-type structures (dopant concentration between 1.5*1016 cm−3 and 1.5*1019 cm−3) on a lightly doped p-type silicon substrate (doped to 1.9*1015 cm−3) have been examined by a photoemission electron microscope equipped with a high-pass energy filter and by an ultra-high vacuum scanning low energy electron microscope. High contrast have been observed between the n-type areas and the p-type substrate and its monotone dependency on the doping level of structures has been manifested. The relation between the energy spectra of photoelectrons and the doping level has been studied, too. The scanning electron microscope images obtained with the landing energy of the primary beam in the low keV range exhibit contrasts similar to those appearing in the full threshold photoemission micrographs.