Patent ID: 7856665

Claim:
A method of making a spectroscopic measurement with a scanning capacitance microscope, including an atomic force microscope, having a conductive sample, a cantilever with a conductive tip and a connection for sending a DC or low frequency bias voltage to the tip, and a vector network analyzer receiving signals reflected from a resonator circuit formed by the sample substrate and the tip in response to first signals, comprising: commanding positioning the tip at a first position far enough from a surface of the sample that the tip does not electrically contact the surface, and commanding emitting a high frequency electromagnetic signal from the network analyzer while said tip is at said first position, and capturing a frequency and amplitude of a second signal reflected from the resonator circuit while said tip is in said first position to determine information indicative of a resonant frequency; setting an excitation frequency of the network analyzer slightly above or below the resonant frequency of the second signal reflected from the resonator circuit, and setting the network analyzer to excite the resonator circuit at said excitation frequency; commanding bringing the tip into contact with the surface of the sample; commanding sending a DC or low frequency bias voltage sweep to the tip; commanding the network analyzer to acquire the amplitude and phase of a third signal for each value of the bias voltage sweep reflected from the resonator circuit; and calculating plots of signal amplitude and phase vs. each bias voltage applied to the tip in a computer.