Second harmonic generation probing of dopant type and density at the Si/SiO2 interface

Abstract

Time-dependent second-harmonic generation (TD-SHG) is shown to be a sensitive, noncontact probe of dopant type and concentration at Si/SiO2 interfaces. TD-SHG signal magnitude increases for n-Si(111)/SiO2, while for p-Si(111)/SiO2 TD-SHG is nonmonotonic. This behavior is interpreted as a consequence of SHG sensitivity to electric fields induced by interfacial charge transfer and trapping.