A Novel Non-Destructive Characterization Method of Electronic Properties of Pre- and Post-Processing Silicon Surfaces Based on Ultrahigh-Vacuum Contactless Capacitance-Voltage Measurements

Abstract

An ultrahigh-vacuum (UHV) contactless capacitance-voltage (C-V) technique was 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 the sample surface by a UHV-gap. The UHV-gap length was shown to be accurately determined by measuring the variation of reflectance of the laser light due to the Goos-Hächen effect. It was demonstrated that the conduction type, carrier 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 ultrathin insulator were successfully characterized by an in-situ and a nondestructive fashion in UHV environments. This method seems to be very powerful for in-situ electronic characterization of “free” and/or “processed” semiconductor surfaces.