A novel non-destructive characterization method of electronic properties of pre- and post-processing silicon surfaces based on ultrahigh-vacuum contactless capacitance-voltage measurements

An ultrahigh-vacuum (UHV) contactless capacitance-voltage (C-V) technique w as developed and applied to various silicon (Si) wafers. The system carries out C-V measurements in a UHV chamber from a field plate separated from th e sample surface by a UHV-gap. The UHV-gap length was shown to be accuratel y determined by measuring the variation of reflectance of the laser light d ue to the Goos-Hachen effect. It was demonstrated that the conduction type, earlier concentration and surface Fermi level position could be determined on the Si surface before and after processing. Surface state distributions such as hydrogen terminated surfaces and Si surface covered with an ultrat hin insulator were successfully characterized by an in-situ and a nondestru ctive fashion in UHV environments. This method seems to be very powerful fo r in-situ electronic characterization of "free" and/or "processed" semicond uctor surfaces.