RF Capacitive Spectroscopy for Contactless Measurements of Resistivity Profiles in Highly Resistive Semiconductor Wafers

In this paper, we present a contactless, capacitive method of estimating the resistivity profiles in the direction perpendicular to the semiconductor wafer using frequency domain impedance analysis. Employing a simple model, we show that the different resistivity distributions inside a wafer affect the frequency dependencies of the measured effective capacitance and the Q-factor. We also demonstrate how to estimate resistivity variation inside the sample from the experimental data: C(ω) and Q(ω).