Phase and amplitude sensitive scanning microwave microscopy/spectroscopy on metal-oxide-semiconductor systems

In this paper, an analytical model for phase and amplitude sensitive scanning microwave microscopy on metal-oxide-semiconductor structures is presented. The phase and amplitude of the microwave signals are calculated as a function of operation frequency, oxide thickness, tip radius, bias, and doping level. For doping profiling applications it is found that both the microwave amplitude and phase signals can be used. Under appropriate operation conditions, the phase signals can be larger by a factor of 40. Series resistances turn out to be problematic as they lead to non-monotonic contrast at low doping levels. The phase and amplitude behavior on a material system with a frequency dependent dielectric constant is also investigated and the possibilities of complex impedance spectroscopy are explored.